bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of the effectiveness of agricultural technologies based on production data
Authors: Stepnykh N.V. , Gilev S.D. , Nesterova E.V. , Zargaryan A.M. , Kopylova S.A.
Published: October 2021

Modern agriculture is characterized by a variety of technologies associated with a multivariance of means of production. Due to the fact that the forces of scientific organizations do not allow to study most of the innovations in agriculture, the analysis of the effectiveness of technologies is possible directly in agricultural enterprises, where a large amount of agronomic and economic information obtained in the specific conditions of the introduction of agricultural practices is accumulated. The purpose of the study was to analyze the effectiveness of modern technologies for growing grain crops according to accounting and agronomic reports of agricultural enterprises of the Kurgan region. The methods of monographic, mathematical, and statistical analysis of data from literary sources, annual reports of agricultural enterprises of the region, as well as data from production fields of the Kurgan Research Institute of Agricultural Sciences were used. The results of the study showed the possibility of obtaining high results in crop production due to different methods of tillage (with and without surface tillage), the use of optimal doses of fertilizers. The reserves of profitability growth are associated with a more accurate use of resources, which is possible when considering the data of each field, thanks to the maintenance of electronic books of the field history, as a variant of a digital management tool in crop production.
Improving the efficiency of maintenance of heavy-duty engines
Authors: Zagorodniy Nikolay , Novikov Alexander , Novikov Ivan
Published: October 2021

The paper deals with the issue of improving the efficiency of heavy-duty engines by restoring worn parts. The influence of the reserve of spare parts on the reliability of the engines is determined. It is proposed to carry out maintenance on centralized bases that serve several auto enterprises. Established: the method of replacing worn elements will reduce the number of engine overhauls.
Preparation process of cold bonded pellets with iron-bearing dust and sludge from steel production process
Authors: Mao Rui , Wang Fei , Xu Yuan , Ren Kun , Wang Guangwei
Published: October 2021

Blast furnace dust (BFD) and converter sludge (CS) were used as raw materials for preparing of cold bonded pellets (CBPs). The results showed that BFD contained high content of C, Fe and harmful element of Zn. Conversely, the CS had more Fe and Ca content and less Zn. BFD particles are mostly large and irregular in shape with poor hydrophilicity, whereas CS particles are generally smaller spherical and could bond together easily. Additionally, the main factors influencing the performance of CBPs are the binder, moisture, and pressing pressure. By controlling the mixing ratio of BFD and CS, selecting the appropriate binder and binder amount, and controlling the moisture and pressure, CBPs with a compressive strength and a falling strength of up to 142.7 N and 8.34 times, respectively, can be prepared, thus meeting the requirements of the rotary hearth furnace and the OxyCup production process.
A Systematic Review of the Potential Effects of Lippia sidoides on Dental Plaque and Periodontal Diseases
Authors: de Assis Ellen Lima , Silveira Felipe Dantas , da Ponte Alan Victor Araújo , Regis Rômulo Rocha
Published: October 2021

Lippia sidoides is a typical shrub from Brazil that has been used in traditional medicine. This is a systematic review on the effect of L. sidoides for controlling dental plaque, gingivitis, and periodontitis. A database search through May 2021 in Medline/PubMed, SCOPUS, BVS, and Web of Science identified 711 reports of which 17 met our inclusion criteria. Five randomized controlled trials and three animal studies were included that compared L. sidoides-based products (toothpaste, mouthrinse, and gel) to cetylpyridinium chloride, chlorhexidine, and placebo products. Among the human studies, a significant antiplaque effect after treatment with L. sidoides-based products was observed in three studies and an antigingivitis effect in two studies, similar to chlorhexidine-based products. One study found superior dental plaque reduction compared to cetylpyridinium chloride mouthrinse. Only one study testing a L. sidoides gel found no
antiplaque effect. Among the animal studies, an L. sidoides mouthrinse significantly reduced calculus in two studies, inflammatory infiltrate in one study, and plaque bacteria and gingivitis in one study. An L. sidoides gel significantly reduced alveolar bone loss and inflammatory response in one study in which mice were submitted to ligature-induced periodontal disease. In general, L. sidoides-based products were effective in reducing dental plaque and calculus formation, as well as clinical signs of gingivitis. As most studies present methodological limitations, these results should be interpreted carefully. Further clinical trials with greater methodological accuracy and control of biases are necessary for the use of L. sidoides-based products in humans to be viable in clinical practice.
Characterization of the Role of Integrin α5β1 in Platelet Function, Hemostasis, and Experimental Thrombosis
Authors: Janus-Bell Emily , Yakusheva Alexandra , Scandola Cyril , Receveur Nicolas , Ahmed Usman Muhammad , Mouriaux Clarisse , Bourdon Catherine , Loubière Cécile , Eckly Anita , Senis Yotis A. , Panteleev Mikhail A. , Gachet Christian , Mangin Pierre H.
Published: October 2021

Objective Integrins are key regulators of various platelet functions. The pathophysiological importance of most platelet integrins has been investigated, with the exception of α5β1, a receptor for fibronectin. The aim of this study was to characterize the role of α5β1 in megakaryopoiesis, platelet function, and to determine its importance in hemostasis and arterial thrombosis.

Approach and Results We generated a mouse strain deficient for integrin α5β1 on megakaryocytes and platelets (PF4Cre-α5−/−). PF4Cre-α5−/− mice were viable, fertile, and presented no apparent signs of abnormality. Megakaryopoiesis appears unaltered as evidence by a normal megakaryocyte morphology and development, which is in agreement with a normal platelet count. Expression of the main platelet receptors and the response of PF4Cre-α5−/− platelets to a series of agonists were all completely normal. Adhesion and aggregation of PF4Cre-α5−/− platelets under shear flow on fibrinogen, laminin, or von Willebrand factor were unimpaired. In contrast, PF4Cre-α5−/− platelets displayed a marked decrease in adhesion, activation, and aggregation on fibrillar cellular fibronectin and collagen. PF4Cre-α5−/− mice presented no defect in a tail-bleeding time assay and no increase in inflammatory bleeding in a reverse passive Arthus model and a lipopolysaccharide pulmonary inflammation model. Finally, no defects were observed in three distinct experimental models of arterial thrombosis based on ferric chloride-induced injury of the carotid artery, mechanical injury of the abdominal aorta, or laser-induced injury of mesenteric vessels.

Conclusion In summary, this study shows that platelet integrin α5β1 is a key receptor for fibrillar cellular fibronectin but is dispensable in hemostasis and arterial thrombosis.
Bis(η5-cyclopentadienyl)[μ-(4b,5,5a-η3:9b,10,10a-η3)-2,3,7,8-tetrakis(trimethylsilyl)benzo[3,4]cyclobuta[1,2-b]biphenylene]-syn-dicobalt (Co–Co), a Dinuclear π-Complex of the Linear [3]Phenylene Framework
Authors: Vollhardt K. Peter C. , Padilla Robin , Houk Kendall N. , Wong Jonathan J.
Published: October 2021

The title compound was made by the reaction of the CpCo-complex of 2,3,7,8-tetrakis(trimethylsilyl) linear [3]phenylene, in which the metal coordinates one of the cyclobutadiene rings, with CpCo(C2H4)2. Because of its relative stability, a syn-dicobalt-bound configuration is indicated rather than its anti alternative.
Epoxyanthracene Derivatives and Dicarbonylation on Benzene Ring via Hexadehydro-Diels–Alder (HDDA) Derived Benzynes with Oxazoles
Authors: Yang Feihu , Zheng Xiaojie , Hu Qiong , Hu Yimin , Lei Yu , Zhu Wenjing
Published: October 2021

A capture reaction of hexadehydro-Diels–Alder (HDDA) derived benzyne with various substituted oxazoles is reported. With methyl, hydrogen, or phenyl as the substituent at 2-position of oxazole, tetraynes afforded epoxyanthracene derivatives or underwent dicarbonylation on benzene ring. The reaction does not require any catalyst or additive. The mechanism behind the reaction was investigated. The obtained polycyclic product structure has potential application value in optoelectronic materials. The availability of dicarbonylated arene implies the uniqueness of HDDA benzyne reaction compared with traditional benzyne.
Catastrophic Concomitant Arterial and Venous Thrombosis in a Mild COVID-19-Positive Patient
Authors: Nugraha Raka A. , Muliawan Hary S. , Nugroho Nyityasmono T. , Ikhsan Muhammad , Adiarto Suko
Published: October 2021

Since its first discovery in late 2019, coronavirus disease 2019 (COVID-19) has been a global burden associated with significant morbidity and mortality. COVID-19 has been correlated with the development of hypercoagulable state that predisposes the patients to a higher risk of thromboembolism. Current evidence suggests higher incidence of thrombosis, particularly venous thrombosis, among hospitalized COVID-19 patients, mostly with critical illness. On the other hand, there is currently no data regarding the incidence of vivid thrombosis in ambulatory patients with mild COVID-19 and the incidence of concomitant arterial and venous thrombosis in COVID-19 is extremely rare. Herein, we describe catastrophic outcomes of concomitant lower limb arterial and venous thrombosis in a patient with mild COVID-19. This report highlights the occurrence of concomitant arterial and venous thrombosis in ambulatory setting and that this phenomenon resulted in catastrophic clinical consequences.
Is DISI Deformity Related to Presence of a Medial Lunate Facet in Patients with Scapholunate Dissociation?
Authors: Goeminne Sofie , Lemmens Laura , Degreef Ilse
Published: October 2021

Background Lunate morphology has been suggested to influence carpal kinematics.

Purpose We investigate a possible relation between presence of a medial lunate facet and dorsal intercalated segment instability (DISI) of the wrist in patients with a scapholunate (SL) dissociation.

Methods We retrospectively reviewed patients diagnosed with SL dissociation between 2000 and 2017. Lunate morphology was categorized based on radiographs and magnetic resonance imaging (MRI), as type I or II according to Viegas and Galley. DISI was defined as radiolunate angle > 15 degrees and SL instability as SL angle > 60 degrees. SL distance > 3 mm was considered as widening and carpal height ratio < 0.5 was considered as carpal collapse. We used descriptive statistics to report on SL instability and DISI in patients with Viegas type I and type II lunates. We calculated kappa to determine agreement between radiographs and MRI and to determine inter- and intraobserver agreement.

Results Of 119 patient files, 79 wrists met the inclusion criteria of which 25 were type I lunates and 54 type II. Similar spreading of the data of both groups was found regarding DISI, SL instability, and SL widening based on radiographic classification of the lunate, even after adding MRI findings. In the presence of carpal collapse, capitate-to-triquetrum distance was higher. We found a substantial inter- and intraobserver agreement for lunate classification.

Conclusion Our results suggest a similar prevalence of DISI deformity or enlarged SL angle in patients with type I or II lunate in presence of SL dissociation. The Viegas classification is a reliable and reproducible classification system.

Level of evidence This is a Level III, cross-sectional study design.
Development of shipboard automatic flow injection analysis—Surface-enhanced Raman spectroscopy instrument toward onsite detection of trace polycyclic aromatic hydrocarbons in water environment
Authors: Zhou Zhifan , Wang Juyong , Xue Wendong , Zou Yisong , Liu Guokun , Tian Zhongqun
Published: October 2021

The qualitative and quantitative analysis of polycyclic aromatic hydrocarbons (PAHs) has been important for the environmental control of persistent organic pollutants for decades. Considering the potential risk of deterioration, degradation, and external pollution during transportation, the development of rapid and onsite detection of trace PAHs is in demand. Here, taking the advantage of high sensitivity of surface-enhanced Raman spectroscopy (SERS), we developed a shipboard instrument by combining a portable Raman instrument and a flow injection device, integrating the sample pretreatment and target detection step by step. The feasibility of the instrument was demonstrated by detecting trace benzo[a]pyrene from different water environments with the lowest detection concentration less than 1 µg/l. The reliable stability and repeatability indicate that in the case of emergency response, the developed flow injection analysis–SERS instrument is very promising for the quantitative and qualitative analysis of diverse organic pollutants other than PAHs in water environments.
Energy conservation for the incompressible inhomogeneous Euler–Korteweg equations in a bounded domain
Authors: Zhang Zhipeng
Published: October 2021

In this paper, we investigate the principle of the energy conservation for the weak solutions of the incompressible inhomogeneous Euler–Korteweg equations in a bounded domain. We provide two sufficient conditions on the regularity of the weak solutions to ensure the energy conservation. Due to the presence of the boundary, we need to impose the boundedness for the velocity and the Besov-type continuity for the normal component of the velocity and the gradient of the density near the boundary.
A monolithic linear motion platform driven by a piezoelectric and fluidic pressure-fed dual mechanism
Authors: Chun Heebum , Kim Jungsub , Lee ChaBum , Kim Hyo-Young
Published: October 2021

This paper presents a novel dual-mode motion mechanism capable of achieving nanopositioning on a monolithic linear motion platform. Unlike conventional dual-mode stages that use piezoelectric (PZT)- and electromagnetic-combined or similar actuation mechanisms comprising two separate motion axes, the dual-mode actuation was developed by combining a PZT for a coarse motion and a fluidic pressure-fed mechanism (FPFM) for a fine motion and was implemented in a monolithic flexure stage fabricated by metal additive manufacturing. The FPFM actuates the flexure stage by pressuring the media in the fluidic channels created inside the flexure spring structures. Experimental tests were performed to investigate the performance of the dual-mode linear motion platform. The stiffness, damping, and frequency response functions of the dual-mode stage were experimentally characterized. The proportional–integral–differential control combined with dual-mode control was employed to control the position of the flexure stage while bidirectionally controlling the flow of compressed air for a fine motion. The FPFM motion showed a good response to 1 nm stepwise input (every 10 psi), and it was implemented to provide up to ∼10 nm fine motion along with the PZT coarse motion (1 µm). The hysteresis characteristics of the FPFM were also characterized and compensated to track the positioning error.
Evaluation of high-dielectric pads for macaque brain imaging at 7 T
Authors: Zhao A. Jie , Liu B. Chunyi , Gao C. Yang , Quan D. Zhiyan , Xia E. Ling , Zhang F. Xiaotong
Published: October 2021

A non-human primate is a valuable model for investigating the structure and function of the brain. Different from the human brain imaging using radio frequency (RF) head coils, in the present study, on a human whole-body 7 T magnetic resonance imaging system, we used an RF knee coil for monkey brain imaging in vivo due to the smaller size of the macaque’s brain compared to that of a human, and particularly, high-dielectric pads were also utilized in order to improve brain imaging performance. Our experimental results suggest that high-dielectric pads can effectively enhance the B1 field strength and receive sensitivity, leading to a higher flip-angle magnitude, an image signal-to-noise ratio, and tissue contrast, and in the meantime, we did not observe elevated receive array element coupling and receive noise amplification nor apparent magnetic susceptibility-induced artifact or distortion, showing that the pads do not introduce adverse RF interferences in macaque brain imaging at 7 T.
Beam power scale-up in micro-electromechanical systems based multi-beam ion accelerators
Authors: Ji Q. , Afridi K. K. , Bauer T. , Giesbrecht G. , Hou Y. , Lal A. , Ni D. , Persaud A. , Qin Z. , Seidl P. , Sinha S. , Schenkel T.
Published: October 2021

We report on the development of multi-beam radio frequency (RF) linear ion accelerators that are formed from stacks of low cost wafers and describe the status of beam power scale-up using an array of 112 beams. The total argon ion current extracted from the 112-beamlet extraction column was 0.5 mA. The measured energy gain in each RF gap reached as high as 7.25 keV. We present a path toward using this technology to achieve ion currents >1 mA and ion energies >100 keV for applications in material processing.
Quantifying the coherent interaction length of second-harmonic microscopy in lithium niobate confined nanostructures
Authors: Amber Zeeshan H. , Kirbus Benjamin , Eng Lukas M. , Rüsing Michael
Published: October 2021

Thin-film lithium niobate (TFLN) in the form of x- or z-cut lithium-niobate-on-insulator has attracted considerable interest as a very promising and novel platform for developing integrated optoelectronic (nano)devices and exploring fundamental research. Here, we investigate the coherent interaction length lc of optical second-harmonic generation (SHG) microscopy in such samples, that are purposely prepared into a wedge shape, in order to elegantly tune the geometrical confinement from bulk thicknesses down to approximately 50 nm. SHG microscopy is a very powerful and non-invasive tool for the investigation of structural properties in the biological and solid-state sciences, especially for visualizing and analyzing ferroelectric domains and domain walls. However, unlike in bulk lithium niobate (LN), SHG microscopy in TFLN is impacted by interfacial reflections and resonant enhancement, both of which rely on film thickness and substrate material. In this paper, we show that the dominant SHG contribution measured on TFLN in backreflection is the co-propagating phase-matched SHG signal and not the counter-propagating SHG portion as is the case for bulk LN samples. Moreover, lc depends on the incident pump laser wavelength (sample dispersion) but also on the numerical aperture of the focussing objective in use. These experimental findings on x- and z-cut TFLN are excellently backed up by our advanced numerical simulations.
Toward the realization of subsurface volumetric integrated optical systems
Authors: Richards Corey A. , Ocier Christian R. , Zhu Jinlong , Goddard Lynford L. , Braun Paul V.
Published: October 2021

Next generation mobile devices and computing architectures would benefit from ultra-high bandwidth technologies that efficiently transport and process optical signals. Subsurface fabrication can address this challenge by forming volumetric photonic integrated circuits with a more compact aerial footprint than planar on-chip circuits. These 3D optical systems may utilize densely packed low-loss, freeform optical interconnects for high volume data transfer. In this Perspective, we provide a comparative overview of the two main methods for subsurface fabrication, including our recently developed SCRIBE process, and assess the advantages and future directions of each approach. After analyzing the underlying technologies, we provide a roadmap of important steps to transition from laboratory demonstrations of individual elements to industrial-scale production of subsurface volumetric photonic integrated circuits.
Hydrodynamic density functional theory for mixtures from a variational principle and its application to droplet coalescence
Authors: Stierle Rolf , Gross Joachim
Published: October 2021

Dynamic density functional theory (DDFT) allows the description of microscopic dynamical processes on the molecular scale extending classical DFT to non-equilibrium situations. Since DDFT and DFT use the same Helmholtz energy functionals, both predict the same density profiles in thermodynamic equilibrium. We propose a molecular DDFT model, in this work also referred to as hydrodynamic DFT, for mixtures based on a variational principle that accounts for viscous forces as well as diffusive molecular transport via the generalized Maxwell–Stefan diffusion. Our work identifies a suitable expression for driving forces for molecular diffusion of inhomogeneous systems. These driving forces contain a contribution due to the interfacial tension. The hydrodynamic DFT model simplifies to the isothermal multicomponent Navier–Stokes equation in continuum situations when Helmholtz energies can be used instead of Helmholtz energy functionals, closing the gap between micro- and macroscopic scales. We show that the hydrodynamic DFT model, although not formulated in conservative form, globally satisfies the first and second law of thermodynamics. Shear viscosities and Maxwell–Stefan diffusion coefficients are predicted using an entropy scaling approach. As an example, we apply the hydrodynamic DFT model with a Helmholtz energy density functional based on the perturbed-chain statistical associating fluid theory equation of state to droplet and bubble coalescence in one dimension and analyze the influence of additional components on coalescence phenomena.
Micro-rheology of a particle in a nonlinear bath: Stochastic Prandtl–Tomlinson model
Authors: Jain Rohit , Ginot Félix , Krüger Matthias
Published: October 2021

The motion of Brownian particles in nonlinear baths, such as, e.g., viscoelastic fluids, is of great interest. We theoretically study a simple model for such a bath, where two particles are coupled via a sinusoidal potential. This model, which is an extension of the famous Prandtl–Tomlinson model, has been found to reproduce some aspects of recent experiments, such as shear-thinning and position oscillations [R. Jain et al., “Two step micro-rheological behavior in a viscoelastic fluid,” J. Chem. Phys. 154, 184904 (2021)]. Analyzing this model in detail, we show that the predicted behavior of position oscillations agrees qualitatively with experimentally observed trends; (i) oscillations appear only in a certain regime of velocity and trap stiffness of the confining potential, and (ii), the amplitude and frequency of oscillations increase with driving velocity, the latter in a linear fashion. Increasing the potential barrier height of the model yields a rupture transition as a function of driving velocity, where the system abruptly changes from a mildly driven state to a strongly driven state. The frequency of oscillations scales as (v0−v0*)1/2 near the rupture velocity v0*, found for infinite trap stiffness. Investigating the (micro-)viscosity for different parameter ranges, we note that position oscillations leave their signature by an additional (mild) plateau in the flow curves, suggesting that oscillations influence the micro-viscosity. For a time-modulated driving, the mean friction force of the driven particle shows a pronounced resonance behavior, i.e., it changes strongly as a function of driving frequency. The model has two known limits: For infinite trap stiffness, it can be mapped to diffusion in a tilted periodic potential. For infinite bath friction, the original Prandtl–Tomlinson model is recovered. We find that the flow curve of the model (roughly) crosses over between these two limiting cases.
Multi-reference approach to the computation of double core-hole spectra
Authors: Tenorio Bruno Nunes Cabral , Decleva Piero , Coriani Sonia
Published: October 2021

Double Core-Hole (DCH) states of small molecules are assessed with the restricted active space self-consistent field and multi-state restricted active space perturbation theory of second order approximations. To ensure an unbiased description of the relaxation and correlation effects on the DCH states, the neutral ground-state and DCH wave functions are optimized separately, whereas the spectral intensities are computed with a biorthonormalized set of molecular orbitals within the state-interaction approximation. Accurate shake-up satellite binding energies and intensities of double-core-ionized states (K−2) are obtained for H2O, N2, CO, and C2H2n (n = 1–3). The results are analyzed in detail and show excellent agreement with recent theoretical and experimental data. The K−2 shake-up spectra of H2O and C2H2n molecules are here completely characterized for the first time.
Band broadening in mobility shift affinity capillary electrophoresis due to pressure-driven flow
Authors: Dutta Debashis
Published: October 2021

Mobility Shift Affinity Capillary Electrophoresis (msACE) presents a simple and powerful approach to determining the equilibrium and kinetic parameters governing the interaction between a variety of analyte and ligand molecules. These determinations often rely on measuring the elution peak profile for the analyte zone when migrated with a steady electric field. However, pressure-gradients applied intentionally or generated due to unwanted differences in the hydrostatic heads at the capillary/channel ends and/or a variation in the electroosmotic flow rate along the analysis column can significantly alter this peak profile introducing error in the estimated parameter values. To account for these alterations, this article describes a mathematical formulation for quantitating band broadening in msACE systems due to a steady pressure-driven flow in the Taylor–Aris dispersion limit with fast analyte-ligand binding kinetics. The current analysis shows that the additional zone dispersion under such conditions can be quantitated using four terms that scale with the square of the Péclet number calculated based on the pressure-driven flow velocity. While the first term among these quantitates the Taylor–Aris dispersion experienced by a neutral tracer advected by the pressure-gradient, the other three terms are proportional to the square of the difference in the diffusion coefficients for the analyte and analyte-ligand complex. Moreover, these latter terms also vary inversely with the Damköhler number computed as the ratio of the rate of reaction over that of diffusive mass transfer with the coefficient for each of the four terms shown to be dependent on the cross-sectional shape of the analysis column.
Entropy of simple fluids with repulsive interactions near freezing
Authors: Khrapak Sergey A. , Yurchenko Stanislav O.
Published: October 2021

Among different thermodynamic properties of liquids, the entropy is one of the hardest quantities to estimate. Therefore, the development of models allowing accurate estimations of the entropy for different mechanisms of interatomic interactions represents an important problem. Here, we propose a method for estimating the excess entropy of simple liquids not too far from the liquid–solid phase transition. The method represents a variant of cell theory, which particularly emphasizes relations between liquid state thermodynamics and collective modes properties. The method is applied to calculate the excess entropy of inverse-power-law fluids with ∝r−n repulsive interactions. The covered range of potential softness is extremely wide, including the very soft Coulomb (n = 1) case, much steeper n = 6 and n = 12 cases, and the opposite hard-sphere interaction limit (n = ∞). An overall reasonably good agreement between the method’s outcome and existing “exact” results is documented at sufficiently high fluid densities. Its applicability condition can be conveniently formulated in terms of the excess entropy itself. The method is also applied to the Lennard-Jones potential but demonstrates considerably lower accuracy in this case. Our results should be relevant to a broad range of liquid systems that can be described with isotropic repulsive interactions, including liquid metals, macromolecular systems, globular proteins, and colloidal suspensions.
Reducing indoor virus transmission using air purifiers
Authors: Dbouk Talib , Roger Frederic , Drikakis Dimitris
Published: October 2021

Air purifiers are limited to small polluting airborne particles and poor air circulation (fan) for bringing airborne particles inside the device. Thus, the optimal utility of domestic air purifiers (DAPs) for eliminating airborne viruses is still ambiguous. This paper addresses the above limitations using computational fluid dynamics modeling and simulations to investigate the optimal local design of a DAP in an indoor space. We also investigate the integrated fan system and the local transport of airborne viruses. Three different scenarios of using standard DAP equipment (144  m3/h) are explored in an indoor space comprising a furnished living room 6×6×2.5  m3. We show that the local positioning of a purifier indoors and the fan system embedded inside it can significantly alter the indoor airborne virus transmission risk. Finally, we propose a new indoor air circulation system that better ensures indoor airborne viruses' local orientation more efficiently than a fan embedded in a standard DAP.
Dilute sodium dodecyl sulfate droplets impact on micropillar-arrayed non-wetting surfaces
Authors: Wang Long-Zan , Huang Xianfu , Yuan Quanzi , Chen Longquan , Yu Ying-Song
Published: October 2021

Impinging dilute sodium dodecyl sulfate (SDS) droplets on micropillar-arrayed polydimethylsiloxane surfaces were experimentally investigated. It was found that the behaviors of impinging droplets greatly depend on surface roughness and SDS concentration. Similar to pure water droplets, there exists a narrow range of dimensionless Weber number, We, for the complete rebound of impacting SDS droplets. The lower and upper limits of impact velocity were theoretically analyzed and compared with experimental data. The addition of SDS could greatly shorten the contact time of bouncing droplets. Besides, surface roughness has little influence on the maximum spreading factor while SDS concentration has an obvious influence and the maximum spreading factor nearly follows a scaling law of We1/4.
Analyzing random lasing spectra of the zinc oxide bulk and the multiple quantum wells by empirical mode decomposition and fast Fourier transform
Authors: Wu Yung-Chi , Lan Yu-Pin , Liu Wei-Rein , Lin Ja-Hon , Lin Bi-Hsuan , Hsieh Wen-Feng
Published: October 2021

Empirical mode decomposition (EMD) was used to efficiently distinguish weak random-cavity emission from large broad spontaneous emission of the ZnO bulk and the multiple quantum wells (MQWs) structures. By fast Fourier transforming (FFT) the EMD results, we obtained the optical cavity lengths of random lasing and their corresponding emission intensity. With increasing pumping power, the EMD-FFT method confirms that the nonlinear trend of the random lasing emission in ZnO bulk and the change in optical cavity length is a result of change in refractive index dispersion due to the bandgap renormalization with high excited carrier density in nonpolar a-plane ZnO MQWs.
Direct numerical simulation of supersonic turbulent expansion corner with shock impingement
Authors: Zhang Zhigang , Tong Fulin , Duan Junyi , Li Xinliang
Published: October 2021

This study conducted a direct numerical simulation of an incident shock wave impinging at an angle of 33.2° on a 12° supersonic turbulent expansion corner at Mach 2.25 to determine the influence of expansion on the physics of interaction. The point of nominal impingement was located at the tip of the expansion corner. This scenario was compared in detail with interactions in the case of a flat plate under the same inflow conditions. The expansion led to a significant reduction in the wall pressure and the size of the separation bubble. The pre-multiplied spectra of the fluctuating wall pressure indicated that the motion induced by the low-frequency shock was strongly inhibited by the presence of an expansion corner. The root mean-squared wall pressure declined rapidly downstream of the corner, and relaxed at a nearly constant level very close to its upstream value. The evolution of the reattached boundary layer was analyzed in terms of its velocity profile, map of anisotropic invariance, and turbulent kinetic energy, and a quick recovery process was clearly identified. Moreover, the analysis of decomposition of the mean skin friction revealed the dominant contribution of the turbulent kinetic energy regardless of the effect of expansion. Unlike in the case of flat-plate interaction, the component of negative spatial growth became positive owing to large positive streamwise heterogeneity, and could be neglected. Bidimensional empirical-mode decomposition was used to decompose the fluctuations into four modes with specific spanwise length scales, and the primary mechanism for the generation of skin friction was linked to small-scale structures in the near-wall region.
Perfect sound absorption of Helmholtz resonators with embedded channels in petal shape
Authors: Duan Mingyu , Yu Chenlei , He Wei , Xin Fengxian , Lu Tian Jian
Published: October 2021

The acoustic metamaterial in the form of a petal-shaped channel embedded Helmholtz resonator (P-CEHR) is proposed for perfect sound absorption. According to theoretical predictions, numerical simulations, and experiments, the P-CEHR achieves perfect low-frequency (e.g., 200 Hz) sound absorption across a deep subwavelength thickness (e.g., 1/34 of the corresponding acoustic wavelength). Compared with the circular-shaped channel embedded Helmholtz resonator, the sound absorption peak and bandwidth of P-CEHR are significantly improved (e.g., increased by 20.9% and 60.0%, respectively) under fixed overall dimensions. Physically, the introduction of the petal shape changes the fluid dynamic characteristics of the channel, resulting in the periodic distribution of particle velocity along the circumferential direction and the expansion of the area of the viscous boundary layer. By adjusting the morphology of the embedded channel, the tortuosity ratio and the relative static flow resistance of the channel can be regulated appropriately, so that the resonator can meet the acoustic impedance matching condition and achieve excellent sound absorption performance. This work provides a method for improving the performance of acoustic absorption metamaterials with built-in air channels and has guiding significance for the control of low-frequency noise.
Capillary transfer: Numerical study of how topology affects the fluid flow rate into a planar microstructure with pseudopotential multiphase Lattice-Boltzmann method
Authors: Pham Robin , Wang Sheng , Chien Heng-Chieh , Chen Chung-Lung
Published: October 2021

We investigate how topology impacts capillary action with the hope of aiding future thermal engineering decisions. Heat pipes and their two-dimensional variant, vapor chambers are essential components in electronics cooling. With thin-film evaporation as the driving force for such high-heat-flux movers, studies have been done to optimize the thermal performance of different designs. However, the fundamental problem of liquid transportation needs to be addressed exclusively: evaporation can only work as long as the new liquid is continuously being replaced. The device achieves this by the capillary process (or wicking) through the thermal ground (or wicks): a configuration of microstructures attached to the device's walls. Some planar topologies of the structure allow for consistent but slower mass feeding; others offer higher bandwidth but with local flow hindrance, creating a pulsating tendency; certain conditions would even block the capillary flow. Surveying the capillary performance of different two-dimensional designs of the thermal ground, we encounter a topological factor that correlates with this mass transfer rate. We incorporate in the factor the wick's width, its height, and the gap between one microstructure to another. An energy model is studied to explain the underlying influence of the structure topology, while Lattice-Boltzmann method is used to evaluate the capillary dynamics inside the thermal ground. With ultra-thin applications in mind, the paper looks at the length scales of micrometers with a wick height of 50 μm. Overall, we find that tightly packed structures pull the most liquid in the same amount of time; however, we find that two core constraints need to be met: sufficient clearance between structures and freedom of mobility.
A numerical investigation of analyte size effects in nanopore sensing systems
Authors: Szuttor Kai , Kreissl Patrick , Holm Christian
Published: October 2021

We investigate the ionic current modulation in DNA nanopore translocation setups by numerically solving the electrokinetic mean-field equations for an idealized model. Specifically, we study the dependence of the ionic current on the relative length of the translocating molecule. Our simulations show a significantly smaller ionic current for DNA molecules that are shorter than the pore at low salt concentrations. These effects can be ascribed to the polarization of the ion cloud along the DNA that leads to an opposing electric dipole field. Our results for DNA shine light on the observed discrepancy between infinite pore models and experimental data on various sized DNA complexes.
A general solution of dewetting flow with a moving contact line
Authors: Diaz M. Elena , Cerro Ramon L.
Published: October 2021

A theoretical model of a moving contact line was developed for a dewetting flow created by removing a flat solid from a liquid. The model introduces the effect of molecular forces in the near vicinity of the moving contact line. The laminar flow representation is based on a combination of streamline functions defined in a molecular domain where molecular forces are predominant and in a macroscopic domain where viscous forces are predominant. The solution realistically displays the details of the viscous flow near the contact line and compares accurately with existing experimental data. The combined molecular-macroscopic solution resolves the hydrodynamic paradox created by a purely viscous model of this flow [Huh, C. and Scriven, L.E., “Hydrodynamic model of the steady movement of a solid/liquid/fluid contact line,” J. Colloid Interface Sci. 35, 85–101 (1971)] shown to be at odds with experimental data [Fuentes, J. and Cerro, R. L. “Flow patterns and interfacial velocities near a moving contact line,” Experiments in Fluids 38(4), 503–510 (2005)].
First- and third-order shear nonlinearities across the structural relaxation peak of the deeply supercooled pharmaceutical liquid indomethacin
Authors: Moch Kevin , Bierwirth S. Peter , Gainaru Catalin , Böhmer Roland
Published: October 2021

Nonlinear rheological properties of viscous indomethacin are studied in the frequency range of its structural relaxation, that is, in a range so far inaccessible to standard techniques involving medium-amplitude oscillatory shear amplitudes. The first- and third-order nonlinearity parameters thus recorded using a sequence of small and large shear excitations in a time efficient manner are compared with predictions from rheological models. By properly phase cycling the shear amplitudes, build-up and decay transients are recorded. Analogous to electrical-field experiments, these transients yield direct access to the structural relaxation times under linear and nonlinear shearing conditions. To demonstrate the broader applicability of the present approach, transient analyses are also carried out for the glass formers glycerol, ortho-terphenyl, and acetaminophen.
Bivariant species mixing and pressure drop within a hybrid periodic modulated microslit
Authors: Haque A. , Nayak A. K. , Weigand Bernhard
Published: October 2021

In this article, a mathematical study is presented on electroosmotic flow (EOF) of power law fluids driven by an external electric field, where the heterogeneity of a microslit is created by multiple wavy triangular modulated polarized wall hurdles. The primary aim of this paper is to demonstrate and depict the mixing performance that generating more retention time and enhancing the interface area, which is evaluated both analytically and computationally. EOF in microchannels is restricted to low Reynolds numbers with a relatively high viscosity effect, which could predict advection domination in flow mixing due to heterogeneities that can supersede the need of flow turbulence. The numerical experiment is performed for the flow phenomena of this novel alternating microgrooves' patterning to generate an intensively transverse flow field, which represents strong reverse flow due to a higher pressure drop. The geometry modification and potential heterogeneity are the key factors to disturb the flow stream by fluid folding and stretching, leading to significant improvement in mixing efficiency. The numerical computations are performed for the nonlinear coupled Nernst–Planck–Navier Stokes equations using a control volume approach over a staggered grid algorithm to elaborate the performance of the electric potential distribution, the external electric field, the flow field, and the species concentration, which are the major contributors of the mixing efficiency. The evaluated results confirm that surface modulation substantially reduces the mass flow rate, effectively resulting in an increase in the retention time of the flow diffusion, which is justified through analytical testing. The nonlinear coupling effects are found to be more pronounced for shear thickening fluids rather than shear thinning and Newtonian solutions, resulting in a low torque corresponding to equilibrium conditions. To achieve a targeted mixing performance, it is observed that flow behavior indices should be optimized in terms of aversion of flow behavior index, viscous dissipation, and yield stress effect.
Collisional excitation of NH by H2: Potential energy surface and scattering calculations
Authors: Pirlot Jankowiak Paul , Kalugina Yulia N. , Ramachandran Ragav , Raffy Guillaume , Dagdigian Paul J. , Lique François
Published: October 2021

Collisional data for the excitation of NH by H2 are key to accurately derive the NH abundance in astrophysical media. We present a new four-dimensional potential energy surface (PES) for the NH–H2 van der Waals complex. The ab initio calculations of the PES were carried out using the explicitly correlated partially spin-restricted coupled cluster method with single, double, and perturbative triple excitations [RCCSD(T)-F12a] with the augmented correlation-consistent polarized valence triple zeta basis set. The PES was represented by an angular expansion in terms of coupled spherical harmonics. The global minimum corresponds to the linear structure with a well depth De = 149.10 cm−1. The calculated dissociation energy D0 is found to be 30.55 and 22.11 cm−1 for ortho-H2 and para-H2 complexes, respectively. These results are in agreement with the experimental values. Then, we perform quantum close-coupling calculations of the fine structure resolved excitation cross sections of NH induced by collisions with ortho-H2 and para-H2 for collisional energies up to 500 cm−1. We find strong differences between collisions induced by ortho-H2 and para-H2. Propensity rules are discussed. The cross sections are larger for fine structure conserving transitions than for fine structure changing ones, as predicted by theory. These new results should help in interpreting NH interstellar spectra and better constrain the abundance of NH in interstellar molecular clouds.
Metal cations drive carbon dioxide’s chemical reduction
Authors: Lopatka Alex
Published: October 2021

Experimental evidence confirms one long-standing hypothesis: Positively charged metal ions stabilize the reaction’s intermediate molecules.
Modeling sound at Stonehenge
Authors: Cox Trevor J.
Published: October 2021

When the prehistoric monument was still intact, reflections between its stones produced a remarkable amount of reverberation and amplified speech by 4 decibels.
Field-theoretic density estimation for biological sequence space with applications to 5′ splice site diversity and aneuploidy in cancer
Authors: Chen Wei-Chia , Zhou Juannan , Sheltzer Jason M. , Kinney Justin B. , McCandlish David M.
Published: October 2021

Significance

Often in computational biology, our data take the form of a set of sequences: for example, a collection of nucleic acid sequences with a shared function. Given such a collection of sequences, how can we estimate the probability distribution that these sequences were drawn from? This problem is important both for identifying other sequences with similar function and because the structure of these probability distributions is often informative about the biophysical and evolutionary processes that generated the observed sequences. Here, we present a method for estimating such probability distributions that generalizes the popular maximum entropy approach. This method is capable of capturing fine details of the distribution in high-density regions where data are plentiful but still behaves conservatively in low-density regions.
Continuous measurements of volatile gases as detection of algae crop health
Authors: Sauer Jon S. , Simkovsky Ryan , Moore Alexia N. , Camarda Luis , Sherman Summer L. , Prather Kimberly A. , Pomeroy Robert S.
Published: October 2021

Significance

Wide adoption of algae cultivation to produce environmentally sustainable biofuels and fine chemicals is currently hampered by large losses (10 to 30%) incurred by grazer infections. We show the usage of real-time chemical ionization mass spectrometry to rapidly identify gaseous indicators of grazer infections in cyanobacteria cultures. Grazing was detected significantly faster (up to 3 d) using real-time mass spectrometry than the current methods of microscopy and qPCR. By employing this technology, cultivators may be empowered to treat grazer infestations sooner, thereby protecting the crop and enhancing profitability.
Recurrent rewiring of the adult hippocampal mossy fiber system by a single transcriptional regulator, Id2
Authors: Luo Wenshu , Egger Matteo , Domonkos Andor , Que Lin , Lukacsovich David , Cruz-Ochoa Natalia Andrea , Szőcs Szilárd , Seng Charlotte , Arszovszki Antónia , Sipos Eszter , Amrein Irmgard , Winterer Jochen , Lukacsovich Tamás , Szabadics János , Wolfer David P. , Varga Csaba , Földy Csaba
Published: October 2021

Significance

Neurons have an exceptional capacity to grow axons and form synaptic circuits during development but not later life. In adults, the lack of circuit formation may support retention of skilled actions and memories but also limits regeneration and repair after injuries and in disorders. Research on developing and damaged neurons has revealed many molecules that help circuit formation and regeneration, and yet factors that could induce axon growth and synapse formation in adult brain neurons remain elusive. Here, we searched for such key molecules and find one that alone can induce complete circuit formation. After engineering a new circuit in adult mice, we also looked into its function and relevance for memories.