bluuebunny/crossref_metadata_2025 huggingface dataset:
Spectroscopic study of self-pulsing discharge with liquid electrode
Authors: Sretenović Goran B. , Saleem Mubbshir , Biondo Omar , Tomei Giulia , Marotta Ester , Paradisi Cristina
Published: May 2021

The article reports and discusses the results of a thorough spectroscopic investigation of the self-pulsing electrical discharge in contact with aqueous media. The discharge occurs between a bare high voltage electrode positioned over the liquid and a grounded ring submerged by the liquid. It is supplied with DC high voltage, but it operates in pulse mode that is determined by the charging and discharging of a parallelly connected capacitor. This type of discharge has attracted our attention due to its complex physics, as well as to its high efficiency in inducing the degradation of highly inert hazardous pollutants present in the water, such as perfluoroalkyl substances. The generated discharge unites several types of plasma in a single discharge cell. It starts as a high temperature (2500 K), high electron density (1016–17 cm−3) spark-like discharge close to the high voltage electrode and then branches into a large number of cooler leaders characterized by one order of magnitude lower electron density (1015 cm−3) in the middle of the gap and finally touches the liquid electrode through a dense network of low temperature (500 K) and low electron density streamers (1014 cm−3). The paper discusses the results of a parametric study that has provided temperature and electron density data in different regions of the discharge. The measurements were thus performed for discharges in ambient air, in synthetic air (an 80/20 N2/O2 mixture) and in argon with, as liquid electrode, either tap or ultrapure water containing a small amount of perfluorooctanoic acid.
Investigation on flow structure and aerodynamic characteristics over an airfoil at low Reynolds number—A review
Authors: Xia Tianyu , Dong Hao , Yang Liming , Liu Shicheng , Jin Zhou
Published: May 2021

This Review summarizes the progress in research on the flow structure and aerodynamic characteristics of an airfoil at a low Reynolds number encountered by near-space low-speed aircrafts and micro-air vehicles. The structures of several kinds of laminar separation bubbles and their effect are discussed by drawing on experimental and numerical results reported in the past few decades. The transition process in the separation bubble is detailed from various perspectives, including the receptive, primary instability, secondary instability, and break-down stage. The process of evolution of a coherent vortex structure that may affect the transition is discussed by analyzing the vortex dynamics in the separation bubble. Combined with the flow characteristics at a low Reynolds number and data on the airfoil, aerodynamic characteristics of the airfoil, such as the nonlinear effect and static hysteresis effect at a low angle of attack, are discussed.
Nonradiative relaxation dynamics in the [Au25-nAgn(SH)18]−1 (n = 1, 12, 25) thiolate-protected nanoclusters
Authors: Pandeya Pratima , Senanayake Ravithree D. , Aikens Christine M.
Published: May 2021

Evaluation of the electron-nuclear dynamics and relaxation mechanisms of gold and silver nanoclusters and their alloys is important for future photocatalytic, light harvesting, and photoluminescence applications of these systems. In this work, the effect of silver doping on the nonradiative excited state relaxation dynamics of the atomically precise thiolate-protected gold nanocluster [Au25-nAgn(SH)18]−1 (n = 1, 12, 25) is studied theoretically. Time-dependent density functional theory is used to study excited states lying in the energy range 0.0–2.5 eV. The fewest switches surface hopping method with decoherence correction was used to investigate the dynamics of these states. The HOMO–LUMO gap increases significantly upon doping of 12 silver atoms but decreases for the pure silver nanocluster. Doped clusters show a different response for ground state population increase lifetimes and excited state population decay times in comparison to the undoped system. The ground state recovery times of the S1–S6 states in the first excited peak were found to be longer for [Au13Ag12(SH)18]−1 than the corresponding recovery times of other studied nanoclusters, suggesting that this partially doped nanocluster is best for preserving electrons in an excited state. The decay time constants were in the range of 2.0–20 ps for the six lowest energy excited states. Among the higher excited states, S7 has the slowest decay time constant although it occurs more quickly than S1 decay. Overall, these clusters follow common decay time constant trends and relaxation mechanisms due to the similarities in their electronic structures.
A nanowire optical nanocavity for broadband enhancement of spontaneous emission
Authors: Kotal Saptarshi , Artioli Alberto , Wang Yujing , Osterkryger Andreas Dyhl , Finazzer Matteo , Fons Romain , Genuist Yann , Bleuse Joël , Gérard Jean-Michel , Gregersen Niels , Claudon Julien
Published: May 2021

To deliver an optimal performance for photonic quantum technologies, semiconductor quantum dots should be integrated in a carefully designed photonic structure. Here, we introduce a nanowire optical nanocavity designed for free-space emission. Thanks to its ultrasmall mode volume, this simple structure offers a large acceleration of spontaneous emission (predicted Purcell factor of 6.3) that is maintained over a 30-nm bandwidth. In addition, a dielectric screening effect strongly suppresses the emission into the 3D continuum of radiation modes. The fraction of spontaneous emission funneled into the cavity mode reaches 0.98 at resonance and exceeds 0.95 over a 100-nm spectral range. Close-to-optimal collection efficiency is maintained over an equivalent bandwidth and reaches a predicted value of 0.54 at resonance for a first lens with a numerical aperture (NA) of 0.75. As a first experimental demonstration of this concept, we fabricate an Au–SiO2–GaAs device embedding isolated InAs quantum dots. We measure a maximal acceleration of spontaneous emission by a factor as large as 5.6 and a bright quantum dot emission (collection efficiency of 0.35 into NA = 0.75). This nanowire cavity constitutes a promising building block to realize advanced sources of quantum light for a broad range of material systems.
Semiconductor nanowire array for transparent photovoltaic applications
Authors: Chen Yang , Hrachowina Lukas , Barrigon Enrique , Beech Jason P. , Alcer David , Lyttleton Roman , Jam Reza Jafari , Samuelson Lars , Linke Heiner , Borgström Magnus
Published: May 2021

The surface area of a building that could potentially be used for Building Integrated Photovoltaics would increase dramatically with the availability of transparent solar cells that could replace windows. The challenge is to capture energy from outside the visible region (UV or IR) while simultaneously allowing a high-quality observation of the outside world and transmitting sufficient light in the visible region to satisfactorily illuminate the interior of the building. In this paper, we show both computationally and experimentally that InP nanowire arrays can have good transparency in the visible region and high absorption in the near-infrared region. We show experimentally that we can achieve mean transparencies in the visible region of 65% and the radiative limit of more than 10% based on measured absorption and calculated emission. Our results demonstrate that nanowire arrays hold promise as a method to achieve transparent solar cells, which would fulfill the requirements to function as windows. In addition, we show that by optical design and by designing the geometry of nanowire arrays, solar cells can be achieved that absorb/transmit at wavelengths that are not decided by the bandgap of the material and that can be tailored to specific requirements such as colorful windows.
Microstructure and mechanical properties of atomic layer deposited alumina doped zirconia
Authors: Piirsoo Helle-Mai , Jõgiaas Taivo , Mändar Hugo , Ritslaid Peeter , Kukli Kaupo , Tamm Aile
Published: May 2021

Atomic layer deposited alumina doped zirconia films can exhibit advanced mechanical properties with potential to increase the suitability of ZrO2 films for mechanically resilient coatings. In the present study, Al2O3-doped ZrO2 films were deposited on a TiN substrate to thicknesses around 100 nm at 300 °C. A zirconia film containing 4.6 mol. % Al2O3 was crystallized in its tetragonal polymorph. Increasing the Al2O3 content up to 5.8 and 8.2 mol. % stabilized the cubic polymorph in the ZrO2-based films. The films with even higher Al2O3 contents remained amorphous. All the crystalline films possessed a preferential grain orientation to extents differing beneath the surface and in the vicinity of the substrate. The most rigid films with hardness up to 15 GPa and elastic modulus above 170 GPa could be obtained when crystallized in the form of cubic ZrO2 stabilized upon doping with Al2O3. For all the crystalline films, the hardness and elastic modulus increased near the substrate.
Recommended Correlations for the Surface Tension of n-Alkanes
Authors: Mulero A. , Cachadiña I. , Bautista D.
Published: May 2021

In previous papers, specific correlations were proposed to reproduce the surface tension values selected for several families of fluids and for wide ranges of temperatures. In this paper, the surface tension of n-alkanes is considered. For that, the data available in DIPPR and DETHERM databases and in Wohlfarth and Wohlfarth [“Surface tension of pure liquids and binary liquid mixtures,” in Landolt-Börnstein, New Series Group IV Physical Chemistry Vol. 16, edited by M. D. Lechner (Springer-Verlag, Berlin, 1997)] and its updated supplements (2008 and 2016) have been compiled. In most cases, a significant number of new data have been added, which were published elsewhere during the last few years and that were not included in the previously mentioned sources. All the data and values available for each fluid have been carefully screened and subsequently fitted to the Guggenheim–Katayama model, which includes two to six adjustable coefficients for each fluid. As a result, recommended correlations for 33 n-alkanes are proposed, providing absolute deviations below 1.65 mN/m and mean absolute percentage deviations below 2.1%.
Phase-field modeling of selective laser brazing of diamond grits
Authors: Li Lu , Li Shuai , Zhang Bi , Fan Tai-Hsi
Published: May 2021

Diamond grit is widely used in cutting, grinding, and polishing tools for its superior mechanical properties and performance in machining hard materials. Selective laser brazing (SLB) of diamond grits is a new additive manufacturing technique that has great potential to fabricate the next generation of high-performance diamond tools. However, fundamental understanding and quantitative analysis for the design and tuning of the SLB process and the resulting bonding efficiency are not yet established as the process is complicated by heating, fusion, wetting, solidification, grit migration, bonding, reaction, and the interplay between these effects. We present a thermodynamically consistent phase-field theoretical model for the prediction of melting and wetting of SLB on diamond grits using a powder-based additive manufacturing technique. The melting dynamics is driven by laser heating in a chamber filled with argon gas and is coupled with the motion of multiple three-phase contact lines. The relevant wetting dynamics, interfacial morphology, and temperature distribution are computationally resolved in a simplified two-dimensional (2D) configuration.
Time-scale ordering in hydrogen- and van der Waals-bonded liquids
Authors: Roed Lisa Anita , Dyre Jeppe C. , Niss Kristine , Hecksher Tina , Riechers Birte
Published: May 2021

The time scales of structural relaxation are investigated on the basis of five different response functions for 1,2, 6-hexanetriol, a hydrogen-bonded liquid with a minor secondary contribution, and 2,6,10,15,19,23-hexamethyl-tetracosane (squalane), a van der Waals-bonded liquid with a prominent secondary relaxation process. Time scales of structural relaxation are derived as inverse peak frequencies for each investigated response function. For 1,2,6-hexanetriol, the ratios of the time scales are temperature-independent, while a decoupling of time scales is observed for squalane in accordance with the literature. An alternative evaluation approach is made on the squalane data, extracting time scales from the terminal relaxation mode instead of the peak position, and in this case, temperature-independent time-scale ratios are also found for squalane, despite its strong secondary relaxation contribution. Interestingly, the very same ordering of response-function-specific time scales is observed for these two liquids, which is also consistent with the observation made for simple van der Waals-bonded liquids reported previously [Jakobsen et al., J. Chem. Phys. 136, 081102 (2012)]. This time-scale ordering is based on the following response functions, from fast to slow dynamics: shear modulus, bulk modulus, dielectric permittivity, longitudinal thermal expansivity coefficient, and longitudinal specific heat. These findings indicate a general relation between the time scales of different response functions and, as inter-molecular interactions apparently play a subordinate role, suggest a rather generic nature of the process of structural relaxation.
Influence of thermal fluctuations on active diffusion at large Péclet numbers
Authors: Dyer O. T. , Ball R. C.
Published: May 2021

Three-dimensional Wavelet Monte Carlo dynamics simulations are used to study the dynamics of passive particles in the presence of microswimmers—both represented by neutrally buoyant spheres—taking into account the often-omitted thermal motion alongside the hydrodynamic flows generated by the swimmers. Although the Péclet numbers considered are large, we find the thermal motion to have a significant effect on the dynamics of our passive particles and can be included as a decorrelation factor in the velocity autocorrelation with a decay time proportional to the Péclet number. Similar decorrelation factors come from swimmer rotations, e.g., run and tumble motion, and apply to both entrainment and far field loop contributions. These decorrelation factors lead to active diffusivity having a weak apparent power law close to Pe0.2 for small tracer-like particles at Péclet numbers appropriate for E. coli swimmers at room temperature. Meanwhile, the reduced hydrodynamic response of large particles to nearby forces has a corresponding reduction in active diffusivity in that regime. Together, they lead to a non-monotonic dependence of active diffusivity on particle size that can shed light on similar behavior observed in the experiments by Patteson et al. [“Particle diffusion in active fluids is non-monotonic in size,” Soft Matter 12, 2365–2372 (2016)].
A vertebrate adaptive radiation is assembled from an ancient and disjunct spatiotemporal landscape
Authors: Richards Emilie J. , McGirr Joseph A. , Wang Jeremy R. , St. John Michelle E. , Poelstra Jelmer W. , Solano Maria J. , O’Connell Delaney C. , Turner Bruce J. , Martin Christopher H.
Published: May 2021

Significance

Most biodiversity evolved in rapid bursts of new species, adaptations, and ecological niches. However, this process of adaptive radiation is poorly understood. We used large-scale genomic sequencing across the entire Caribbean range of pupfishes to understand why radiation in this group is restricted to a single Bahamian island. We found that twofold higher gene flow to this island brought in new combinations of ancient adaptive mutations needed for colonizing novel ecological niches of scale-eating and snail-eating. Adaptation occurred in stages: first selection on feeding behavior, then selection for trophic morphology, and finally refinement through gene coding change. We demonstrate that young, localized radiations can emerge from a vast pool of adaptive genetic variation spread across time and space.
AP-3–dependent targeting of flippase ATP8A1 to lamellar bodies suppresses activation of YAP in alveolar epithelial type 2 cells
Authors: Kook Seunghyi , Wang Ping , Meng Shufang , Jetter Christopher S. , Sucre Jennifer M. S. , Benjamin John T. , Gokey Jason J. , Hanby Hayley A. , Jaume Alexa , Goetzl Laura , Marks Michael S. , Guttentag Susan H.
Published: May 2021

Significance

We identify AP-3–mediated targeting of flippase ATP8A1 to lamellar bodies, lysosome-related organelles that store pulmonary surfactant for secretion from alveolar epithelial cells. Genetic AP-3 loss in cultured alveolar epithelial cells and in thepearlmouse model causes ATP8A1 retention in early sorting and/or recycling endosomes and concomitant accumulation of phosphatidylserine on endosomal membranes. This in turn elicits a toxic gain-of-function through Yes-activating protein and initiates lung injury programs that may contribute to progressive lung fibrosis associated with Hermansky Pudlak syndrome type 2.
Selective MAP1LC3C (LC3C) autophagy requires noncanonical regulators and the C-terminal peptide
Authors: Bischoff Megan E. , Zang Yuanwei , Chu Johnson , Price Adam D. , Ehmer Birgit , Talbot Nicholas J. , Newbold Michael J. , Paul Anurag , Guan Jun-Lin , Plas David R. , Meller Jarek , Czyzyk-Krzeska Maria F.
Published: May 2021

LC3s are canonical proteins necessary for the formation of autophagosomes. We have previously established that two paralogs, LC3B and LC3C, have opposite activities in renal cancer, with LC3B playing an oncogenic role and LC3C a tumor-suppressing role. LC3C is an evolutionary late gene present only in higher primates and humans. Its most distinct feature is a C-terminal 20-amino acid peptide cleaved in the process of glycine 126 lipidation. Here, we investigated mechanisms of LC3C-selective autophagy. LC3C autophagy requires noncanonical upstream regulatory complexes that include ULK3, UVRAG, RUBCN, PIK3C2A, and a member of ESCRT, TSG101. We established that postdivision midbody rings (PDMBs) implicated in cancer stem-cell regulation are direct targets of LC3C autophagy. LC3C C-terminal peptide is necessary and sufficient to mediate LC3C-dependent selective degradation of PDMBs. This work establishes a new noncanonical human-specific selective autophagic program relevant to cancer stem cells.
Upregulation of VCAM-1 in lymphatic collectors supports dendritic cell entry and rapid migration to lymph nodes in inflammation
Authors: Arasa Jorge , Collado-Diaz Victor , Kritikos Ioannis , Medina-Sanchez Jessica Danielly , Friess Mona Carina , Sigmund Elena Caroline , Schineis Philipp , Hunter Morgan Campbell , Tacconi Carlotta , Paterson Neil , Nagasawa Takashi , Kiefer Friedemann , Makinen Taija , Detmar Michael , Moser Markus , Lämmermann Tim , Halin Cornelia
Published: May 2021

Dendritic cell (DC) migration to draining lymph nodes (dLNs) is a slow process that is believed to begin with DCs approaching and entering into afferent lymphatic capillaries. From capillaries, DCs slowly crawl into lymphatic collectors, where lymph flow induced by collector contraction supports DC detachment and thereafter rapid, passive transport to dLNs. Performing a transcriptomics analysis of dermal endothelial cells, we found that inflammation induces the degradation of the basement membrane (BM) surrounding lymphatic collectors and preferential up-regulation of the DC trafficking molecule VCAM-1 in collectors. In crawl-in experiments performed in ear skin explants, DCs entered collectors in a CCR7- and β1 integrin–dependent manner. In vivo, loss of β1-integrins in DCs or of VCAM-1 in lymphatic collectors had the greatest impact on DC migration to dLNs at early time points when migration kinetics favor the accumulation of rapidly migrating collector DCs rather than slower capillary DCs. Taken together, our findings identify collector entry as a critical mechanism enabling rapid DC migration to dLNs in inflammation.
A new design for an ultra-wideband microwave metamaterial absorber
Authors: Yu Yongjun , Sun Pingyuan , Wang Yunfan , Chen Zhaoyang
Published: May 2021

In this paper we propose a new design for an ultra-wideband microwave metamaterial absorber. This metamaterial absorber has a sandwich structure, and the top metal pattern is periodically arranged on the copper background. This metamaterial absorber is combined with Fe–Co composites and metamaterials, which solves the narrow-band problem of microwave absorption. We realize an absorptivity of more than 90% in the 2.16–18 GHz frequency band for normal incidence. The thickness of the structure is 0.61 mm (about 1/48.8 wavelength at the central frequency). The performance of the proposed absorber is not sensitive to the polarization of incident waves.
An arduino experiment for measuring the base amplification factor of NPN transistors
Authors: Mohamed Ahmed Obaid
Published: May 2021

The hFE of a transistor, or commonly known as the hybrid parameter forward current gain, is one of the important factors that characterizes the working of a transistor in any circuit. So designing such an experiment with readily available materials would help STEM students gain more intuition about the working principle of transistors in general. In this experiment we had used an Arduino UNO microcontroller along with some resistors and by using Ohm’s law we were able to deduce a formula for the hFE (hybrid parameter current gain) of any npn transistor used in the circuit, just by measuring the voltages across the input and output resistors used along with the transistor in a common emitter configuration.
Investigation of the energy harvesting performance of a Lambda-shaped piezoelectric energy harvester using an analytical model validated experimentally
Authors: Qing Haitao , Jeong Sinwoo , Jeong Se Yeong , Sung Tae Hyun , Yoo Hong Hee
Published: May 2021

The principal objective of this paper is to show the efficient and reliable energy harvesting performance of a Lambda-shaped piezoelectric energy harvester (LPEH). The equations of motion of the harvester were derived based on Euler–Bernoulli beam theory. The accuracy of the analytical model was validated by the finite element method and experiment. Then, using the analytical model, the energy harvesting performance of the harvester was compared to that of a conventional cantilever piezoelectric energy harvester. It was found that the LPEH generated much more power than the cantilever piezoelectric harvester when the same amount of substrate and piezoelectric materials were used. Additionally, the effects of the harvester shape angle and excitation direction of the proposed harvester on the energy harvesting performance were investigated. The results showed that the LPEH could produce reliable power even though the harvester shape angle and excitation direction varied. Owing to such reliable energy harvesting characteristics, the proposed harvester has the practical advantages of fitting within limited space and functioning under uncertain excitation direction conditions.
High-resolution x-ray spectra of carbon monoxide reveal ultrafast dynamics induced by long UV pulse
Authors: Liu Ji-Cai , Savchenko Viktoriia , Kimberg Victor , Gel’mukhanov Faris , Odelius Michael
Published: May 2021

In theoretical simulations of a UV + x-ray pump-probe (UVX-PP) setup, we show that frequency detuning of the pump UV pulse acts as a camera shutter by regulating the duration of the UVX-PP process. This two-photon absorption with long overlapping UV and x-ray pulses, allowing for high spectral resolution, thereby provides information about ultrafast dynamics of the nuclear wave packet without the requirement of ultrashort pulses and controlled delay times.

In a case study of carbon monoxide, the calculated UVX-PP spectra of the O1s
−12π
1 and C1s
−12π
1 core-excited states show different vibrational profiles. The interference of intermediate vibrational states reveals details of nuclear dynamics in the UVX-PP process related to a variable duration time controlled by the UV detuning. Both O1s
−12π
1 and C1s
−12π
1 pump-probe channels display a splitting of the spectral profile, which however is associated with different physical mechanisms. At the O1s
−12π
1 resonance, the observed dispersive and non-dispersive spectral bands intersect and result in destructive interference.
Distortion of the local density of states in a plasmonic cavity by a quantum emitter
Authors: Cuartero-González Alvaro , Manjavacas Alejandro , Fernández-Domínguez Antonio I
Published: May 2021

We investigate how the local density of states in a plasmonic cavity changes due to the presence of a distorting quantum emitter. To this end, we use first-order scattering theory involving electromagnetic Green’s function tensors for the bare cavity connecting the positions of the emitter that distorts the density of states and the one that probes it. The confined, quasistatic character of the plasmonic modes enables us to write the density of states as a Lorentzian sum. This way, we identify three different mechanisms behind the asymmetric spectral features emerging due to the emitter distortion: the modification of the plasmonic coupling to the probing emitter, the emergence of modal-like quadratic contributions and the absorption by the distorting emitter. We apply our theory to the study of two different systems (nanoparticle-on-mirror and asymmetric bow-tie-like geometries) to show the generality of our approach, whose validity is tested against numerical simulations. Finally, we provide an interpretation of our results in terms of a Hamiltonian model describing the distorted cavity.
Study of half metallic ferromagnetism, transport and mechanical properties of X0.9375Ti0.0625Te (X = Ca, Sr, and Ba) alloys: for spintronics application
Authors: Ismail Khawar , Albalawi Hind , Murtaza G , Al-Muhimeed Tahani I , AlObaid Abeer A , Mahmood Q
Published: May 2021

The diluted magnetic semiconductors (DMS) are emerging materials for spitronic applications. Therefore, X0.9375Ti0.0625Te (X = Ca, Sr, and Ba) Alloys for electronic, magnetic, and transport properties while 25% doping of Ti for elastic properties have been elaborated. The band structures and density of states ensures the half metallic ferroamgneitsm (HMF) and 100% spin polarization has been ensured by Heisenberg classical model. The quantum ferromagnetism has been disccused in terms of double exchange mechanism, crystal field energy Ecry, and exchange energies

Δ

x

d

and

Δ

x

p
d

.

The negative pd exchange energy, and exchange constants guarantee the ferromagnetism is due to quantum exchange of electrons rather than clustering. The effect of electrical and thermal conductivities of electrons quantum, potential gradient effect and power factors are elaborated by BoltzTraP code. The elastic properties are elucidated by elastic constants C11, C12, C44, elastic moduli, Pugh’s (B/G), and Poisson’s (υ) ratios. Therefore, the studied alloys are taken as potential materials for spintronic.
On a new SEIRDEoIoepidemic model eventually initiated from outside with delayed re-susceptibility and vaccination and treatment feedback controls
Authors: De la Sen Manuel , Ibeas Asier , Garrido Aitor
Published: May 2021

This paper studies a new extended SEIR (susceptible-exposed-infectious recovered) epidemic model which incorporates the contribution of infective contagions to the resident population from infective exposedEoand infectiousIooutsiders as well as eventual delayed re-susceptibility by partial loss of immunity. It is referred to as aSEIRDEoIosince the dead individuals caused by the disease are defined as a new subpopulation. The potential contribution of the disease propagation of non-resident external infected travellers is considered as well as a re-susceptibility which increases the susceptible numbers and a parallel loss of immunity caused by a potential delayed re-infection. The model is also studied under eventual vaccination and treatment controls each one of them including two additive terms including proportional feedback of the susceptible and infectious, respectively, as well as control actions being independent of the population numbers. The disease-free and endemic equilibrium points are characterized, as well as their dependence on the control gains, and their stability properties are also studied. It is found that they are unique and only one of the two is a global attractor depending on the model parameter values. Typically, the value of the basic reproduction number is crucial to characterize the stability or, alternatively, that of the coefficient transmission rate provided that the remaining parameters are prefixed. The controls are also useful to increase the admissible minimum threshold of the infection force compatible with the stability of the disease-free equilibrium point. Simulation results are given, some of them related to parameterizations of usefulness related to the recent COVID-19, while others to a varicella case study.
Long range interactions in cosmology: implications for neutrinos
Authors: Esteban Ivan , Salvado Jordi
Published: May 2021

Cosmology is well suited to study the effects of long range
interactions due to the large densities in the early Universe. In
this article, we explore how the energy density and equation of
state of a fermion system diverge from the commonly assumed ideal
gas form under the presence of scalar long range interactions with a
range much smaller than cosmological scales. In this scenario,
“small”-scale physics can impact our largest-scale
observations. As a benchmark, we apply the formalism to
self-interacting neutrinos, performing an analysis to present and
future cosmological data. Our results show that the current
cosmological neutrino mass bound is fully avoided in the presence of
a long range interaction, opening the possibility for a
laboratory neutrino mass detection in the near future. We also
demonstrate an interesting complementarity between neutrino
laboratory experiments and the future EUCLID survey.
Reversible quantum state transfer in a three-mode optomechanical system
Authors: Zhang Chun-Ling , Chen Xiang , Liao Chang-Geng , Lin Xiu-Min
Published: May 2021

Quantum state transfer between two nodes is a basic task of long-distance quantum communication. In this paper, we propose a general protocol to transfer quantum state between optical and microwave modes in a three-mode optomechanical system based on transitionless quantum driving. By choosing a well-designed path, the reversible transfer between optical and microwave modes can be achieved in the shorter time than adiabatic passage method. We further apply this idea for implementing the quantum state transfer between optical or microwave and mechanical modes. Numerical simulation results show that the protocol is robust against the cavity decay and mechanical damping. Therefore, this work provides a new method for quantum state transfer between two optical modes with distinct wavelengths in the optomechanical system, which may have great application prospect in quantum communication.
Hadron resonances as rovibrational states *
Authors: Bernardo Douglas L. , Bastos Cristiano C. , Pavão Antonio C.
Published: May 2021

A rovibrational model, including anharmonic, centrifugal, and Coriolis corrections, is used to calculate π, K,N, and Ʃ orbital and radial resonances. The four orbital excitations of the π meson correspond to the b(1235), π2(1670), b
3(2030), and π4(2250) resonances. Its first four radial excitations correspond to the π(1300), π(1800), π(2070), and π(2360) resonances. The orbital excitations of the K meson are interpreted as the K
1(1270), K
2(1770), K
3(2320), and K
4(2500) resonances; its radial excitations correspond to the K(1460) and K(1830) resonances. The N orbital excitations are identified with the N(1520), N(1680), N(2190), N(2220), and N(2600) resonances. The first four radial excitations of the N family correspond to the N(1440), N(1880), N(2100), and N(2300) resonances. The orbital excitations of the Ʃ baryon are associated with the Ʃ(1670), Ʃ(1915), Ʃ(2100), and Ʃ(2250) resonances, whereas its radial excitations are identified with the Ʃ(1660), Ʃ(1770), and Ʃ(1880) resonances. The proposed rovibrational model calculations show a good agreement with the corresponding experimental values and allow for the prediction of hadron resonances, thereby proving to be useful for the interpretation of excited hadron spectra.
Feedforward modulation of gamma motor neuron activity can improve motor command accuracy
Authors: Dideriksen Jakob , Negro Francesco
Published: May 2021

Objective. Coactivation of gamma and alpha motor neuron activity ensures that muscle spindle responsiveness is maintained during muscle contractions. However, some evidence suggests that the activity of gamma motor neurons is phase-advanced with respect to that of alpha motor neurons during manual control tasks. We hypothesized that this might be a deliberate control strategy to maximize movement accuracy. Approach. Using a computational model of the neural activation of a muscle and its type Ia sensory feedback to the motor neurons, we systematically investigated the impact of the phase difference between oscillatory descending input to alpha and dynamic gamma motor neurons. Specifically, the amplification of the alpha motor neuron drive to the muscle was investigated as a function of the frequency of the synaptic input (1–9 Hz individually or superimposed) and the alpha–gamma phase difference (0–2π). Main results. Simulation results showed that when the phase advance of the dynamic gamma drive resulted in delays between muscle velocity and type Ia afferent feedback similar to those previously observed experimentally, low-frequency components (1 and 2 Hz) of the motor neuron synaptic input were amplified (gain up to 1.7). On the other hand, synaptic input at higher frequencies was unaffected. Significance. This finding suggests that by imposing a phase advance of the input to dynamic gamma motor neurons, components of the neural drive usually associated with voluntary control are amplified. In this way, our study suggests that this neural strategy increases the control-to-neural-noise ratio of the motor output during movement.
On inclusive distance vertex irregularity strength of small identical copies of star graphs
Authors: Susanto F , Betistiyan C N , Halikin I , Wijaya K
Published: May 2021

For a simple graphG, an inclusive distance vertex irregulark-labeling ofGis a mapping λ :V (G)→ {1,2,…,k} such that all the vertex-weights are pairwise distinct, where the weight of a vertexv, denoted bywt(v), is the sum of labels of vertices in the close neighborhood of the vertexv. The minimumkfor which the graphGhas an inclusive distance vertex irregulark-labeling is called the inclusive distance vertex irregularity strength ofG,dis^(G). Here we introduce a new lower bound fordis^(G)and determine the exact value of the inclusive distance vertex irregularity strength for identical copies of star graphs, especially 2Snand 3Sn.
Edge even graceful labeling of some corona graphs
Authors: Jayantara D , Purwanto  , Irawati S
Published: May 2021

Elsonbaty and Daoud introduced a labeling of graph with p vertices and q edges called edge even graceful labeling i.e. a bijective function f of the edge set E(G) into the set {2,4,6, . . . , 2q} such that the induced function f*:V(G) → {0,2,4, . . ., 2k − 2}, defined as f*(x) = (∑
xy∈E(G)
f(xy)) mod(2k), is an injective function, where k = max(p, q). The corona G
1 ⨀ G
2 of graphs G
1 and G
2 is the graph obtained by taking one copy of G
1, which has p
1 vertices, and p
1 copies of G
2, and then joining the ith vertex of G
1 by an edge to every vertex in the ith copy of G2
. Some path and cycle-related graph which are edge even graceful has been studied by Elsonbaty and Daoud. This study we construct the corona graph of P
2 and Pn
and the corona of Sn
and K
1. In this paper, we prove that P
2 ⨀ Pn
, when n ≡ 0,4, or 6 mod(8), and (Sn
⨀ K
1) – v
0, when n is even and v
0 is a vertex of degree 1 joining to the center of the star Sn
, are admit edge even graceful labeling.
Compactness and completeness properties of M-metric spaces
Authors: Nisa’ A A , Hasanah D
Published: May 2021

An M-metric space is a generalization of a partial metric space. There have been some research investigating the relations between partial metric spaces and M-metric spaces. Theorems and properties prevailing in partial metric spaces are extended in M-metric spaces. In this paper, we study some compactness and completeness properties in M-metric spaces based on the similar properties in partial metric spaces. We also give completeness relation between M-metric spaces and partial metric spaces.
Projection pursuit regression and principal component regression on statistical downscaling using artificial neural network for rainfall prediction in Jember
Authors: Putri C D , Hadi A F , Anggraeni D , Riski A
Published: May 2021

Rainfall forecasting is essential for Indonesia, which is an agricultural country. Forecasting to see the rainfall needed to anticipate the danger of drought that will harm farmers. However, due to the complexity of topography and the interactions between the oceans, land, and atmosphere in Indonesia, it is difficult to predict rainfall. Therefore, Statistical Downscaling (SD) is needed to provide accurate rainfall predictions by considering the information about global atmospheric circulation obtained from the General Circulation Model (GCM). Statistics Downscaling (SD) modeling is a basic regression model based on the functional relationship between local scales, which is the response variable with the Global Circulation Model (GCM) global scale as a predictor variable. The Statistics Downscaling (SD) method used is Principal Component Regression (PCR) and Projection Pursuit Regression (PPR). The prediction of both methods was conducted by an Artificial Neural Network (ANN). The results showed that the prediction of rainfall in Jember using the PPR + ANN method (with the RMSE value of 79.58723) had better accuracy than the PPR, PCR, and PCR + ANN methods, which had RMSE values of 103.7539, 112.337 and 83.62029, respectively.
Comparing the Principal Regression Analysis Method with Ridge Regression Analysis in Overcoming Multicollinearity on Human Development Index (HDI) Data in Regency/City of East Java in 2018
Authors: Yoantika A F , Susiswo
Published: May 2021

East Java Province is one of the densely populated provinces. The population density in the province of East Java does not hamper the welfare of its people. The welfare of the people in the province of East Java can be seen through the Human Development Index (HDI), which includes elements of life expectancy, education, and economy. According to the Central Statistics Agency (BPS) of East Java, the HDI level from 2017 to 2018 has increased, but this data experiences a case of multicollinearity. Researchers compared the Principal Regression Analysis method with Ridge Regression Analysis in overcoming the multicollinearity. The conditions taken are methods that have a small MSE value and a large R
2 value. Based on the results and discussion, the Main Component Regression Analysis method has an MSE value of 2.51 and an R
2 value of 91.0%, the Ridge Regression Analysis Method has an MSE value of 0,00071 and an R
2 of 97.7%. The provisions obtained are the value of MSE Regression Ridge is smaller than the value of MSE Regression Main Components and the value of R
2 Regression Ridge is greater than the value of R
2 Main Components. So, the best method in overcoming the multicollinearity problem in the Regency / City Human Development Index (HDI) data in East Java in 2018 is the Ridge Regression Analysis method.
BYM CARBayes Model on data of unemployment in East Java and thus mapping using LISA analysis
Authors: Lestari T E , Aliyah R R
Published: May 2021

East Java is the biggest province in Indonesia with 38 regions that contribute to much unemployment in Indonesia. This article aims to model unemployment in each region by taking any factor that significantly influences the number of unemployment using the BYM CARBayes model. The previous research about spatial modeling on unemployment data are using the SAR and SEM model, and the BYM CARBayes model is usually used for disease mapping. In this research, use the BYM CARBayes model on the data of unemployment in East Java. Furthermore, the fitted number of unemployment is used to map each region in East Java with LISA analysis. The mapping of each region is used to determine the region that has an outlier of unemployment with the number of spatial auto correlation is calculated using Moran’I analysis. The modeled data using the BYM CARBayes give the result that the total population and percentage of high school graduates affect the number of unemployment significantly and negatively. The number of the working-age population, GDP, and the minimum wages in each region are affecting the number of unemployment significantly and positively. The map of each region in East Java using the number of unemployment gives 3 regions with an outlier of unemployment. There are Sidoarjo regency, Gresik Regency, and Surabaya city.
Spline estimation method in nonparametric regression using truncated spline approach
Authors: Widyastuti D A , Fernandes A A R , Pramoedyo H
Published: May 2021

A parametric regression approach is used when the shape of the regression curve is known, and the nonparametric approach is used when the shape of the regression curve is unknown, the parametric regression model is still forced as a model of data patterns, it will cause inaccurate conclusions if the form of the function is not known. The truncated spline approach can be used to estimate curves in nonparametric regression models using a knot basis. The curve estimation method used is Weighted Least Square (WLS) for the truncated spline approach. In this study, the nonparametric regression model was implemented on fertilizer subsidy data in East Java. This study aims to examine comprehensively the factors that influence the satisfaction of the farming community. The response variable used in this study is the Courage of Field Extension Officers (Y), while the predictor variables include: Farmers National Culture (X1), Financial Reward for Field Extension Officers (X2), and Leadership Role (X3). The novelty of this research is trying to do regression modeling in which the whole relationship between the response variable and the predictor variable is non-linear. The results of the linearity assumption test show that all predictor variables show a non-linear relationship to the response variable, so it needs to be solved by nonparametric regression. The coefficient of determination shows that the variability of Courage of Field Extension Officers can be explained by 87,65% in the model, while the remaining 12,35% is explained by factors that are not included in the model.
Control strategy of HIV/AIDS model with different stages of infection of subpopulation
Authors: Habibah U , Trisilowati  , Tania T R , Alfaruq L U
Published: May 2021

We formulated mathematical model of HIV/AIDS with two different stages of infection subpopulation with Antiretroviral (ARV) treatment as control strategy. We applied optimal control theory to minimize HIV-infected subpopulation using the Pontryagins-Minimum Principle. Numerical solution was conducted by solving the optimally system using the sweep backward and forward method. The results showed that by giving ARV in the model could decrease the infected subpopulation significantly.
About one of the mathematical models of viscous flow incompressible fluid above sandy bottom
Authors: Aripov M M , Rajabov J SH , Settiev SH R
Published: May 2021

In this research we propose a mathematical model for the flows of a viscous incompressible fluid along an inclined plane under the action of gravity over a sandy bottom. The analysis was carried out in the linear instability of the flow and reduced the problem to finding the eigenvalues. Investigated and analyzed the questions of wave formation on the free and bottom surfaces of the liquid. The regions of flow instability are determined for any Froude numbers. Obtained results were compared with experimental data and with the results of other authors on this topic.
Concretization of nonlinear constitutive relations by results of uniaxial compression and indentation experiments
Authors: Astapov Yu , Markin A , Sokolova M , Khristich D
Published: May 2021

A method for the experimental specification of the variant of the Hencky–Murnaghan constitutive relations is proposed. A series of compression and indentation experiments of a number of specimens made of highly elastic materials is carried out on the experimental stand. An iterative procedure for determining constants from experiments on inhomogeneous deformation is developed. The convergence of the iterative process is investigated. The values of the constants of the Hencky–Murnaghan model are found for materials of two types. It is found that the Hencky–Murnaghan model describes the results of indentation experiments on a wider range of deformations than the Hencky model.
To the question of calculation of amendments to the Navier – Stokes equation
Authors: Gladkov S O , Aung Zaw
Published: May 2021

In the paper provides a detailed conclusion of the Navier-Stokes equation using the classic Boltzmann equation to the third order in the free length path of the molecules. It is noted that the biharmonic component of the Laplace’s operator will play an important role in the research of wrap flow of fluid of nanoparticles.
Some exact solutions of the heat conduction equation in parallelepiped obtained by the fast expansions method
Authors: Goryainov V V , Kuznetsov S F , Nikiforova O Yu , Voronkova I S
Published: May 2021

An analytical solution to the boundary value problem for the Poisson equation in a parallelepiped was obtained in general form using the fast expansions method. The construction of exact solutions of the heat conduction equation for the cases of an internal source depending on coordinates was shown in the work. The study of the influence of the variability of the internal source on the propagation of heat in the body at the same initial temperatures at the parallelepiped vertices was carried out. In this case, the heat in the body will be transferred only in those directions in which the internal source is changed.
About one-dimensional inhomogeneity of elastic characteristics of materials
Authors: Gotsev D V , Kovalev A V , Sporykhin A N , Shashkin A I
Published: May 2021

The analysis of existing methods for modeling the elastic characteristics of materials is carried out. It is taken into account the one-dimensional continuous inhomogeneity of the elastic characteristics. In contrast to the known monotone functional dependencies that describe the distribution of mechanical characteristics of elastic bodies along one direction, we propose models for describing inhomogeneous elastic properties of materials that are non-monotonically distributed along one coordinate. An approximate analytical solution of the Lame problem is obtained for a specific non-monotonic distribution of the displacement modulus along the radial coordinate. The solution is obtained in the form of a convergent sequence of approximations. A numerical experiment is performed for specific values of the approximating coefficients and the results are analyzed.
Theory of thin shells as a spatial two-dimensional continuum in an oblique system of coordinates
Authors: Kozlov Vladimir A , Kashirina Darya A
Published: May 2021

In contrast to the known approaches in the theory of shells, based on certain assumptions, and the traditional reduction of a three-dimensional problem to a two-dimensional one, in this paper, static and geometric relations are obtained from the position of the interaction of linear forces and moments in a spatially curved two-dimensional continuum. This approach was applied by E. Reissner, but in an orthogonal grid and for physical components. Relations are presented in tensor, vector, and scalar forms.