bluuebunny/crossref_metadata_2025 huggingface dataset:
Bird’s eye view of molecular clouds in the Milky Way
Authors: Spilker Andri , Kainulainen Jouni , Orkisz Jan
Published: September 2022

Context. The kinematics of molecular gas are crucial for setting the stage for star formation. One key question related to the kinematic properties of gas is how they depend on the spatial scale.

Aims. We aim to describe the CO spectra, velocity dispersions, and especially the linewidth-size relation of molecular gas from cloud (parsec) scales to kiloparsec scales in a complete region within the Milky Way disk.

Methods. We used the census of molecular clouds within 2 kpc from our earlier work, together with CO emission data for them from the literature. We studied the kinematics and the Larson relations for the sample of individual clouds. We also mimicked a face-on view of the Milky Way and analysed the kinematics of the clouds within apertures of 0.25–2 kpc in size. In this way, we describe the scale-dependence of the CO gas kinematics and Larson’s relations.

Results. We describe the spectra of CO gas at cloud scales and in apertures between 0.25 and 2 kpc in our survey area. The spectra within the apertures are relatively symmetric, but show non-Gaussian high-velocity wings. At cloud scales, our sample shows a linewidth-size relation σv = 1.5 · R0.3±0.1 with a large scatter. The mass-size relation in the sample of clouds is MCO = 794 · R1.5±0.5. The relations are also present for the apertures at kiloparsec-scales. The best-fit linewidth-size relation for the apertures is σv = 0.5 · R0.35±0.01, and the best-fit mass-size relation is MCO = 229 · R1.4±0.1. A suggestive dependence on Galactic environment is seen. Apertures closer to the Galactic centre and the Sagittarius spiral arm have slightly higher velocity dispersions. We explore the possible effect of a diffuse component in the survey area and find that such a component would widen the CO spectra and could flatten the linewidth-size relation. Understanding the nature of the possible diffuse CO component and its effects on observations is crucial for connecting Galactic and extragalactic data.
Mechanism of heterogeneous flow—solid substrate interaction on the formation of coatings of different thicknesses using different types of spray accelerators
Authors: Borisov Sergey , Gloukhovskaya Julia , Dobrovolskiy Sergey , Myakochin Alexander , Podporin Igor
Published: September 2022

Physical processes of the inleakage of a supersonic heterogeneous flow of air-powder mixture to a solid substrate, tested on the experimental setup designed for applying protective coatings by a cold spray method, are considered. The interaction of a particle with a flat plane and cylindrical solid substrates, the multilayer coatings and the application of coatings using spray accelerators of different configurations are considered. A mathematical model is demonstrated based on the equation of energy balance in the impact area intended to estimate the interaction between a particle and a solid substrate during impact, as well as examples of results calculated using this model. Methods for calculation of the thickness of the coating applied to flat plane and cylindrical substrates are described. The features of one-step and multi-step coating applications with and without additional exposures are described. As an example, the results of testing the coating for porosity are given. A list of factors and additional exposures affecting the strength of the coating is given.
Self-oscillations in a certain Belousov–Zhabotinsky model
Authors: Kondratieva Liudmila , Romanov Aleksandr
Published: September 2022

We consider the dynamic properties of a system of three differential equations known as the oreganator model. This model depends on four external parameters and describes one of the periodic Belousov–Zhabotinsky reactions. We obtain broad conditions for the parameters that ensure the existence of nonstationary steady-state regimes in oregonator model. With classical values of the parameters, the localization of the limit (at a long time) dynamics in the phase space has been improved. In fact, using numerical analysis, we significantly narrow the bounded region of the phase space containing the trajectories of the system. An iterative procedure is proposed for the approximate localization of closed trajectories (cycles) of the system on algebraic surfaces inR3. A promising problem of theoretical substantiation of the numerical convergence of this procedure is posed.
Fuzzy controller synthesis algorithm with complete data on the object state
Authors: Luneva Svetlana , Luneva Anna
Published: September 2022

The application of the classical control theory to nonlinear and linear objects control problems in some cases may not give effective results. Due to this, fuzzy controller synthesis methods for objects controlling have been developed based on fuzzy sets and fuzzy logic methods. A suggested method makes it possible to construct a fuzzy system without the help from human experts. The algorithm for this method consists of three steps: on step 1 the known input data ranges are determined and divided into fuzzy regions to form membership functions; on step 2 the data pairs are formed and then used to generate a fuzzy rules table; on step 3 the membership functions are scaled for specific values, so the fuzzy system works more correct. The method has shown it’s good performance in the underwater vehicle stabilization problem with complete data on the object state.
Methods and algorithms for determining the main quasi-homogeneous forms of polynomials and power series
Authors: Nefedov Viktor
Published: September 2022

Methods are proposed that allow one to determine the special forms of polynomials and power series used in solving a number of practical problems. The most important of them are the construction of necessary and sufficient conditions for an extremum for polynomials and power series, as well as checking matrices forD-stability arising in the study of ecosystem stability. This special forms (the so-called main quasi-homogeneous polynomial forms) are generalizations of the concept of a homogeneous polynomial form. They correspond to the sum of the terms of the polynomial belonging to some face of the Newton polytope of this polynomial. In some cases, the main quasi-homogeneous polynomial forms necessary for research can also be determined for power series (in particular, when constructing necessary and sufficient conditions for an extremum). In the case of polynomials, two cases are investigated separately: the selection of all the main forms of the polynomial and the selection of the main forms corresponding to the faces of the Newton polytope in its “southwestern” part (such forms also can be distinguished for an arbitrary power series), since both cases have their practical applications. Practically applicable methods are described for each of these cases. Several methods are considered sequentially (starting with a simple enumeration and ending with a method with a significant reduction in the number of options in the enumeration). The last (most economical) method is described as a practically realizable algorithm. A practically realizable rather economical algorithm for solving an auxiliary problem is described—finding the set of corner points of the Newton polytope.
Application of the modified self-organizing migration algorithm MSOMA in optimal open-loop control problems of switching systems
Authors: Panteleev Andrei , Rakitianskii Vladislav
Published: September 2022

The article discusses the application of the metaheuristic algorithm of global constrained optimization for solving the problem of finding the optimal open-loop control for nonlinear switching deterministic dynamical systems. The quality of control is assessed by the value of the functional defined on individual trajectories. The optimal control problem is reduced to a parametric optimization problem, which is solved using theMSOMA algorithm, which belongs to the evolutionary group. The MSOMA algorithm is a new algorithm based on the SOMA self-organizing migration algorithm. The modification consists in identifying three leaders among the individuals forming the current population. For each member of the population, two clones are generated with the same position. Thus, in fact, three populations are generated, each of which then realizes a migration cycle (evolutionary process) relative to one of the three selected leaders. A step-by-step algorithm for piecewise-constant, piecewiselinear, quadratic spline and cubic spline methods of control laws approximation is proposed. The effectiveness of the proposed method is demonstrated by the example of solving optimal control problems for switching systems with two and three subsystems. The influence of the parameters of the MSOMA algorithm on the quality of the obtained result is investigated. Comparison of the operation of the algorithm with the known solution is carried out.
Empirical model of the viscosity of an epoxy binder at the initial stage of the polymerization process
Authors: Rusakov Sergey , Gilev Valeriy , Rakhmanov Alexey
Published: September 2022

This article presents the results of an experimental study and numerical simulation of the kinetics of curing of an epoxy binder at the initial stage of the polymerization process. Object of research: two-component composition of epoxy resin L and hardener EPH 161, certified as a binder for composite materials for aerospace purposes. The ordinary differential equation is used as the basic model for describing the polymerization process. The values of the material parameters required to perform the calculation operations were obtained by the rheological method using the analysis of changes in the viscosity of the binder depending on the time and temperature of polymerization. Isothermal and non-isothermal polymerization cases are considered. The modes in which the increase in the temperature of the process leads to a decrease in the viscosity of the epoxide composition, despite the polymerization process, were highlighted. The estimates of the model parameters obtained by processing the data of full-scale experiments are also given.
Spectral representation of stochastic integration operators
Authors: Rybakov Konstantin
Published: September 2022

The spectral representation for stochastic integration operators with respect to the Wiener process is proposed in the form of a composition of spectral characteristics used in the spectral form of mathematical description for control systems. This spectral representation can be defined relative to the various orthonormal bases. For given deterministic square-integrable kernels, the spectral characteristic of a stochastic integration operator is determined as an infinite random matrix. The main applications of such a representation suppose solving linear stochastic differential equations and modeling multiple or iterated Stratonovich stochastic integrals. Specific formulas are provided that allow to represent the spectral characteristic for the stochastic integration operator, the kernel of which is the Heaviside function, relative to Walsh functions and trigonometric functions.
Learning curves in ERCP during advanced endoscopy training: a Canadian multicenter prospective study
Authors: Khan Usman , Khan Rishad , Benchimol Eric , Salim Misbah , Telford Jennifer , Enns Robert , Mohamed Rachid , Forbes Nauzer , Sandha Gurpal , Kohansal Ali , Mosko Jeffrey , Chatterjee Avijit , May Gary , Waschke Kevin , Barkun Alan , James Paul D.
Published: September 2022

Background and study aims Growing emphasis on quality and patient safety has supported the shift toward competency-based medical education for advanced endoscopy trainees (AETs). In this study, we aimed to examine Canadian AETs learning curves and achievement of competence using an ERCP assessment tool with strong evidence of validity.

Methods This prospective study was conducted at five institutions across Canada from 2017–2018. Data on every fifth procedure performed by trainees were collected using the United Kingdom Joint Advisory Joint Advisory Group of Gastrointestinal Endoscopy (JAG) ERCP Direct Observation of Procedural Skills (DOPS) tool, which includes a four-point rating scale for 27 items. Cumulative sum (CUSUM) analysis was used to create learning curves for overall supervision ratings and ERCP DOPS items by plotting scores for procedures performed during training.

Results Eleven trainees who were evaluated for 261 procedures comprised our sample. The median number of evaluations by site was 49 (Interquartile range (IQR) 31–76) and by trainee was 15 (IQR 11–45). The overall cannulation rate by trainees was 82 % (241/261), and the native papilla cannulation rate was 78 % (149/191). All trainees achieved competence in the “overall supervision” domain of the ERCP DOPS by the end of their fellowship. Trainees achieved competency in all individual domains, except for tissue sampling and sphincteroplasty.

Conclusions Canadian AETs are graduating from fellowship programs with acceptable levels of competence for overall ERCP performance and for the most specific tasks. Learning curves may help identify areas of deficiency that may require supplementary training, such as tissue sampling.
Angehörige von Delir-patienten im Fokus der Therapiebegleitung
Authors: Ewers Cedric
Published: September 2022

Wie kann man Angehörige von Delirpatienten helfen, das Delir zu verstehen? Dieser Frage ging Autor Cedric Ewers nach und entwickelte einen Flyer, der nicht nur das Delir verständlich und kompakt erklärt, sondern Angehörigen auch Informationen liefert, wie sie den Betroffenen helfen und sie unterstützen können.
Catalytic Generation of Radicals from Nitroalkanes
Authors: Kosaka Kohei , Matsushita Naoki , Nakao Yoshiaki , Kashihara Myuto , Notsu Shunta , Osawa Ayumi
Published: September 2022

A new protocol for the catalytic denitrative generation of radicals from nitroalkanes was disclosed. 9-Fluorenol acts as a single-electron transfer catalyst that reduces nitroalkanes to promote the C-NO2 bond cleavage, followed by the formation of alkyl radicals. The obtained radicals participate in diverse transformations such as hydrogenation, Giese addition, spirocyclization, and Minisci reactions by using appropriate trapping reagents. The present system outperforms conventional methods using tin hydrides in terms of cost, toxicity, and experimental operations.
Imaging of Bone Marrow: From Science to Practice
Authors: Aparisi Gómez Maria Pilar , Ayuso Benavent Carmen , Simoni Paolo , Musa Aguiar Paula , Bazzocchi Alberto , Aparisi Francisco
Published: September 2022

The study of the bone marrow may pose important challenges, due to its changing features over the life span, metabolic stress, and in cases of disease or treatment. Bone marrow adipocytes serve as storage tissue, but they also have endocrine and paracrine functions, contributing to local and systemic metabolism.

Among different techniques, magnetic resonance (MR) has the benefit of imaging bone marrow directly. The use of advanced MR techniques for bone marrow study has rapidly found clinical applications. Beyond the clinical uses, it has opened up pathways to assess and quantify bone marrow components, establishing the groundwork for further study of its implications in physiologic and pathologic conditions.

We summarize the features of the bone marrow as an organ, address the different modalities available for its study, with a special focus on MR advanced techniques and their addition to analysis in recent years, and review some of the challenges in interpreting the appearance of bone marrow.
Degenerative Lumbar Spine Disease: Imaging and Biomechanics
Authors: Lacroix Maxime , Nguyen Christelle , Burns Robert , Laporte Amandine , Rannou François , Feydy Antoine
Published: September 2022

Chronic low back pain (CLBP) is one of the most common diagnoses encountered when considering years lived with disability. The degenerative changes of the lumbar spine include a wide spectrum of morphological modifications visible on imaging, some of them often asymptomatic or not consistent with symptoms. Phenotyping by considering both clinical and imaging biomarkers can improve the management of CLBP. Depending on the clinical presentation, imaging helps determine the most likely anatomical nociceptive source, thereby enhancing the therapeutic approach by targeting a specific lesion. Three pathologic conditions with an approach based on our experience can be described: (1) pure painful syndromes related to single nociceptive sources (e.g., disk pain, active disk pain, and facet joint osteoarthritis pain), (2) multifactorial painful syndromes, representing a combination of several nociceptive sources (such as lumbar spinal stenosis pain, foraminal stenosis pain, and instability pain), and (3) nonspecific CLBP, often explained by postural (muscular) syndromes.
Update on Interventional Radiology of the Spine
Authors: Filippiadis Dimitrios K. , Masala Salvatore , Lucatelli Pierleone , Kelekis Alexis
Published: September 2022

Interventional radiologists now perform spinal interventions routinely for diagnostic and therapeutic purposes. New technologies for the management of spine pathologies have emerged with promising results in terms of safety and efficacy. Interventional radiology techniques in the spine include percutaneous biopsy and therapies for intervertebral disk herniation or spinal stenosis, facet and sacroiliac joint pathologies, vertebral and sacral fractures, and metastases. These techniques can also be easily combined one with the other or to further therapeutic approaches including systemic therapies, surgical approaches, and radiotherapy. This review provides a comprehensive overview of current percutaneous imaging-guided interventional radiology techniques in the spine. It will help readers become familiar with the most common indications, learn about different technical considerations during performance, and review the available evidence. Controversies concerning new products and technical approaches are also addressed.
Imaging of Spine Infections
Authors: Chianca Vito , Chalian Majid , Harder Dorothee , Del Grande Filippo
Published: September 2022

The incidence of spondylodiskitis has increased over the last 20 years worldwide, especially in the immunodepressed population, and it remains a complex pathology, both in terms of diagnosis and treatment. Because clinical symptoms are often nonspecific and blood culture negative, imaging plays an essential role in the diagnostic process. Magnetic resonance imaging, in particular, is the gold standard technique because it can show essential findings such as vertebral bone marrow, disk signal alteration, a paravertebral or epidural abscess, and, in the advanced stage of disease, fusion or collapse of the vertebral elements. However, many noninfectious spine diseases can simulate spinal infection. In this article, we present imaging features of specific infectious spine diseases that help radiologists make the distinction between infectious and noninfectious processes.
The impact of regulation-based constraints on portfolio selection: The Spanish case
Authors: Grizickas Sapkute E. , Sánchez-Granero M. A. , López García M. N. , Trinidad Segovia J. E.
Published: September 2022

Discussion about the effect of constraints in portfolio selection is a popular topic in finance. In this paper, we test the portfolio performance under the existence of regulatory constraints. This paper tries to provide evidence of whether the existence of regulatory constraints translates into a better long-term performance of investment funds, one of the most important investment vehicles for citizens. We show the returns and their relationship with the portfolio’s risk, compared to the same set without the usage of these constraints. The results state that, when using regulation as the constraining factor, we obtain more efficient portfolios.
Finding the skeletons in complex liquid closets
Authors: Lim Alane
Published: September 2022

Method skeletonizes complex fluid interfaces to accurately depict flow without compromising information.
Forecasting large-scale distributed photovoltaics based on subsidies and policy in China
Authors: Ikenson Ben
Published: September 2022

Economic model may smooth transition to clean energy grid
The ghost fields and the BV extension for finite spectral triples
Authors: Iseppi Roberta A.
Published: September 2022

After arguing why the Batalin–Vilkovisky (BV) formalism is expected to find a natural description within the framework of noncommutative geometry, we explain how this relation takes form for gauge theories induced by finite spectral triples. In particular, we demonstrate how the two extension procedures appearing in the BV formalism, that is, the initial extension via the introduction of ghost/anti-ghost fields and the further extension with auxiliary fields, can be described in the language of noncommutative geometry using the notions of the BV spectral triple and total spectral triple, respectively. The construction is presented in detail for all U(2)-gauge theories induced by spectral triples on the algebra M2(C). Indications are given on how to extend the results to U(n)-gauge theories for n > 2.
Pyroreflectometry as a technique for the accurate measurement of very high temperatures in molten materials
Authors: Turquais Benjamin , Sans Jean-Louis , Davoust Laurent , Delacroix Jules , Journeau Christophe , Piluso Pascal , Chikhi Nourdine
Published: September 2022

Experimental research into severe nuclear accidents often requires the accurate measurement of high temperatures of molten materials. Measurements of very high temperatures (1500–2500 °C) in liquid materials using standard pyrometry can entail uncertainties in the order of 5%–10%. Pyroreflectometry is a powerful technique with the potential to significantly reduce these uncertainties. A method is proposed to optimize pyroreflectometry temperature measurements in the 1500–2500 °C range and to allow more easily the detection of the solid–liquid phase transition. The originality of this research essentially relies on the use of pyroreflectometry based on two wavelengths (1.3 and 1.55 μm) and its application to liquid materials at high temperature, which implies to adapt technological elements and metrological procedures. The proposed procedure first requires temperature calibration, which is undertaken using three eutectic fixed-point cells, reducing temperature uncertainty. Second, precise settings are adopted to enable reflectivity measurements on specular surfaces, such as the surfaces of molten metals. Pyroreflectometry measurements on liquid surfaces have been validated on an iron sample. Subsequently, the application of pyroreflectometry at very high temperatures was validated on various materials: metal (iron and 18MND5 steel), oxide (alumina), and carbide (rhenium–carbon eutectic). For each of these samples, the uncertainties of temperature measurements in the 1500–2500 °C range were estimated in the range of 1%–2%, performing well against standard pyrometry measurements. The principal difficulties encountered during the pyroreflectometry characterization were the fine-tuning of parameters (optical head orientation and lens focusing) to enable measurements on highly specular surfaces and ensuring inert interactions between the samples and the crucible.
Arbitrary amplitude ion-acoustic supersolitons in negative ion plasmas with two-temperature superthermal electrons
Authors: Kumar Kishan , Mishra M. K.
Published: September 2022

Arbitrary amplitude ion-acoustic supersolitons are investigated with two-temperature superthermal electrons in an unmagnetized negative ion plasma. In this study, we have considered the plasma containing two cold ion species with different masses, ion concentration and charge multiplicity, and two superthermal (non-Maxwellian) electrons. The energy integral equation has been derived by using the Sagdeev pseudopotential technique. We have investigated that both negative and positive potential supersolitons and solitons can exist in the selected domain of Mach number. A numerical analysis shows that the ion-acoustic supersolitons appear below the acoustic speed (Ms). The amplitude of the supersoliton is found larger than the soliton. The formation of solitons and supersolitons (both polarity) is analyzed by phase portrait of the dynamic of the plasma system. The plasma system also supports the coexistence of compressive and rarefactive solitons for a particular set of plasma parameters. The present study is focused on ion-acoustic solitary and supersolitary waves in the D-and F-regime of Earth's ionosphere and experimentally produced plasmas (Ar+, F−) and (Ar+, SF−6) ion species. The present investigation may be helpful in understanding the nonlinear behavior of supersoliton and soliton in space and laboratory plasmas, where negative ions are present with superthermal electrons at two temperatures.
Compensating cylindrical Hohlraum mode 4 asymmetry via capsule thickness tailoring and effects on implosions
Authors: Dewald E. L. , Clark D. S. , Casey D. T. , Khan S. F. , Mariscal D. , Nicola P. Di , MacGowan B. J. , Hartouni E. P. , Rubery M. S. , Choate C. , Nikroo A. , Smalyuk V. A. , Landen O. L. , Ratledge M. , Fitzsimmons P. , Farrell M. , Mauldin M. , Rice N.
Published: September 2022

Previously, hydrodynamic simulations [Clark et al., Phys. Plasmas 23, 072707 (2016)] suggested that precisely tailoring the capsule ablator thickness (shimming) could counterbalance cylindrical Hohlraum Legendre P4 drive asymmetries at the capsule in laser indirect drive implosions. As a result, the stagnated deuterium–tritium (DT) fuel areal density P4 asymmetry is reduced, potentially resulting in a nuclear yield increase. Inflight radiographs of various level of shimmed capsules with plastic (CH) ablators showed that shims can indeed control the in-flight capsule shell P4 asymmetry, with a linear sensitivity to shim amplitude that is close to analytic estimates and simulations. Furthermore, the stagnated DT fuel areal density P4 asymmetry inferred from downscattered neutron imaging was reduced when the capsule shim was applied, in agreement with simulations matching the inflight shell asymmetry. A nuclear yield improvement via shim was not observed, as predicted, likely due to implosion instabilities and as built capsule shim deviations from an ideal P4 shape.
Dynamic damage characteristics of rock under multiple loads during high-voltage pulse fragmentation
Authors: Zhao Yong , Liu Yi , Xiong Liangli , Huang Shijie , Zhang He , Wang Tianyu , Liu Siwei , Lin Fuchang
Published: September 2022

To analyze the damage characteristics of rocks during high-voltage pulse fragmentation (HVPF), two kinds of loads, shockwave and cavity, are determined by optical observation, and the pressure–time characteristics of these two and their mechanism of damage to rocks in mesoscopic view are analyzed. A model of dynamic damage characteristics of brittle rock under multiple loads is established, which includes numerical calculation and discrete element simulation. In the discrete element simulation, the rock is simplified as a circular region without reflection boundary with a certain size of the circular hole inside, and the grains in the region are discretized as rigid spheres with a definite bonding relationship. The shockwave is considered the time-varying pressure loaded to the grains of the circular hole, and the cavity is considered the quasi-static pressure loaded to the grains on both sides of the fracture. The results of the model show that shear cracks and tensile cracks are produced during the shockwave action, but tensile cracks are predominant. The shockwave acts as a preload for the expansion of cracks, and the damage radius is small. Most of the cracks in HVPF are caused by the cavity. A comparison of the numerical calculation results with the discrete element simulation results shows that the model can describe the distribution characteristics of cracks under multiple loads, which lays a foundation for further analysis of the internal mechanism of HVPF.
Economic modeling of distributed photovoltaic penetration considering subsidies and countywide promotion policy: An empirical study in Beijing
Authors: Yang Shu-Xia , Zhang Yang , Cheng Xiao-Yu
Published: September 2022

Distributed photovoltaic power generation will not only help to achieve the strategic targets of peaking carbon emissions and carbon neutrality but also cause a series of impacts on the power grid at the same time. Forecasting the long-term development of regionally distributed photovoltaics can provide a reference for power grid planning and stable operation. In this paper, considering the effect of factors such as subsidies and countywide promotion policy of photovoltaics, a forecasting model for the development tendency of regionally distributed photovoltaics based on system dynamics is established. Then, taking Beijing as an example, an empirical analysis is carried out, and the effect of the proportion of self-consumption and the time when the subsidy is adjusted on distributed photovoltaic penetration is explored through sensitivity analysis. The simulation results show that the installed capacity achieved by the countywide promotion policy will become the main source of the installed capacity growth of distributed photovoltaics in Beijing after 2024. To continuously boost distributed photovoltaic penetration, relevant policymakers should consider the appropriate time when the subsidy is adjusted according to the installation cost of photovoltaic systems.
Integrating machine learning with mechanistic models for predicting the yield strength of high entropy alloys
Authors: Liu Shunshun , Lee Kyungtae , Balachandran Prasanna V.
Published: September 2022

Accelerating the design of materials with targeted properties is one of the key materials informatics tasks. The most common approach takes a data-driven motivation, where the underlying knowledge is incorporated in the form of domain-inspired input features. Machine learning (ML) models are then built to establish the input–output relationships. An alternative approach involves leveraging mechanistic models, where the domain knowledge is incorporated in a predefined functional form. These mechanistic models are meticulously formulated through observations to validate specific hypotheses and incorporate elements of causality missing from data-driven ML approaches. In this work, we demonstrate a computational approach that integrates mechanistic models with phenomenological and ML models to rapidly predict the temperature-dependent yield strength of high entropy alloys (HEAs) that form in the single-phase face-centered cubic (FCC) structure. Our main contribution is in establishing a quantitative relationship between the HEA compositions and temperature-dependent elastic constants. This allows us to improve the treatment of elastic constant mismatch to the solid solution strengthening effect in the mechanistic model, which is important for reliable prediction of yield strength. We accomplish this by combining Bayesian inference with ensemble ML methods. The outcome is a probability distribution of elastic constants which, when propagated through the mechanistic model, yields a prediction of temperature-dependent yield strength along with the uncertainties. The predicted yield strength shows good agreement with published experimental data, giving us confidence in applying the developed approach for the rapid search of novel FCC-based HEAs with excellent yield strength at various temperatures.
Perspective on optimal strategies of building cluster expansion models for configurationally disordered materials
Authors: Xie Jun-Zhong , Zhou Xu-Yuan , Jiang Hong
Published: September 2022

Cluster expansion (CE) provides a general framework for first-principles-based theoretical modeling of multicomponent materials with configurational disorder, which has achieved remarkable success in the theoretical study of a variety of material properties and systems of different nature. On the other hand, there remains a lack of consensus regarding what is the optimal strategy to build CE models efficiently that can deliver accurate and robust prediction for both ground state energetic properties and statistical thermodynamic properties at finite temperature. There have been continuous efforts to develop more effective approaches to CE model building, which are further promoted by recent tremendous interest of applying machine learning techniques in materials research. In this Perspective, we present a critical review of recent methodological developments in building CE models for multicomponent materials, with particular focus on different approaches and strategies proposed to address cluster selection and training data generation. We comment on the pros and cons of different methods in a general formalism and present some personal views on the prospects of theoretical approaches to multicomponent materials.
Faraday instability of non-Newtonian fluids under low-frequency vertical harmonic vibration
Authors: Huo Qiang , Wang Xiaopeng
Published: September 2022

Resonance Acoustic Mixing® (RAM) technology applies an external low-frequency vertical harmonic vibration to convey and mix the non-Newtonian fluid across space. However, although this method is used for various applications, its mechanism is yet not well understood. In this paper, we investigate the Faraday instability of power-law non-Newtonian fluids in RAM utilizing theory and simulations. According to the Floquet analysis and the dimensionless Mathieu equation, the critical stable region besides the stable region and the unstable region is discovered. Based on the numerical solutions of the two-dimensional incompressible Euler equations for a prototype Faraday instability flow, the temporal evolution of the surface displacement and the mechanism of Faraday waves for two cases are explored physically. For the low forcing displacement, there are only stable and critical stable regions. The surface deformation increases linearly and then enters the steady-state in which the fluctuation frequency is twice the vertical harmonic vibration. For the large forcing displacement, there are only stable and unstable regions. Under the effect of the inertial force, both cases have a sudden variation after the brief stabilization period. Furthermore, a ligament structure is observed, which signals that the surface is destabilized. In addition, a band-like pressure minimum distribution below the interface is formed. The fluid flows from the bottom to the crest portion to balance the pressure difference, which raises the crest.
Stacking two superconducting nanowire single-photon detectors via membrane microchip transfer
Authors: Chen Shi , Zhao Qing-Yuan , Zheng Kai , Tao Xu , Guo Jia-Wei , Liu Zhen , Wang Hui , Kong Ling-Dong , Hao Hao , Huang Yang-Hui , Xu Tao , Tu Xue-Cou , Zhang La-Bao , Jia Xiao-Qing , Chen Jian , Kang Lin , Wu Pei-Heng
Published: September 2022

Multilayer superconducting nanowire single-photon detectors (SNSPDs) have exhibited several advantages, such as increased detection efficiency, reduced polarization sensitivity, and scaling up to large arrays. However, monolithic fabrication of such multilayer devices is challenging. In this work, a hybrid integration method has been introduced by etching SNSPDs into the membrane microchips, followed by the pick and place transferring process. This method has been verified by stacking two SNSPDs orthogonally. Both detectors show near saturated detection efficiencies and low timing jitters. Furthermore, thermal coupling effects have been observed between the two SNSPDs. The photon detection pulses from either detector can trigger the other one almost deterministically with a latency of several nanoseconds. This method offers a flexible way to fabricate multilayer SNSPDs or integrate them with other heterogeneous devices.
Computational model for predicting the dynamic dissolution and evolution behaviors of gases in liquids
Authors: Ren Zhipeng , Li Deyou , Wang Hongjie , Liu Jintao , Li Yong
Published: September 2022

Dynamic gas–liquid mass transfer behaviors are widely encountered in the chemical, environmental, and engineering fields. Referring to the Singhal full cavitation model, Henry's law, and Zhou's experiments, we innovatively developed a computational model for dissolved and released mass-transfer to revolutionize the independent unidirectional gas-to-liquid or liquid-to-gas theory. From a new perspective, coupled dissolution and evolution mechanisms were defined similar to how condensation and evaporation were redefined, where dissolution and release mass-transfer prediction methods that can be applied to three-dimensional calculations were integrated for the first time. The dissolved gas saturation concentration was the criterion for determining the direction of mass transfer. According to the theoretical derivation, the driving forces behind the dissolution and evolution are the remaining undissolved gas and real-time solution concentration, respectively. We confirmed the validity of the proposed dynamic model using an unsteady simulation after a grid independence study and an experimental verification of dissolved oxygen concentration in plug-discharge flow. The difference in dissolved oxygen concentration between simulations of this computational model and experiments could be low as 2.0%. A higher dissolved oxygen concentration was distributed in the flow separation and throat gas–liquid blocking zones, indicating that a surge in the flow velocity led to an increased mass transfer rate. In addition, a parametric study was conducted to consider the impact of the oxygen volume fraction and initial dissolved oxygen concentration on the real-time concentration.
The open Haldane–Shastry chain: thermodynamics and criticality
Authors: Finkel Federico , González-López Artemio
Published: September 2022

We study the thermodynamics and criticality of the su(m|n) Haldane–Shastry chain of BC

N
type with a general chemical potential term. We first derive a complete description of the spectrum of this model in terms of BC

N
-type motifs, from which we deduce a representation for the partition function as the trace of a product of site-dependent transfer matrices. In the thermodynamic limit, this formula yields a simple expression for the free energy per spin in terms of the Perron–Frobenius eigenvalue of the continuum limit of the transfer matrix. Evaluating this eigenvalue we obtain closed-form expressions for the thermodynamic functions of the chains with m, n ⩽ 2. Using the motif-based description of the spectrum derived here, we study in detail the ground state of these models and their low energy excitations. In this way we identify the critical intervals in chemical potential space and compute their corresponding Fermi velocities. By contrast with previously studied models of this type, we find in some cases two types of low energy excitations with linear energy-quasimomentum relation. Finally, we determine the central charge of all the critical phases by analyzing the low-temperature behavior of the expression for the free energy per spin.
Variation of Saturation Indices (SIcal) with respect to Calcite Mineral at Kalisirah and Jumbleng Springs, South Gombong Karst, Central Java, Indonesia
Authors: Mahrizkhal D S , Priambada A P , Al-Ghozali M Q , Rahmawati A I , Cahyadi A , Haryono E , Adji T N
Published: September 2022

This research was conducted in two main springs, namely Kalisirah and Jumbleng springs, located on the north side of the South Gombong karst area, Central Java, Indonesia. The objective of this study was to determine the temporal variation of the saturation indices with respect to the mineral calcite in the two springs. Water samples were taken 24 times at each spring during dry, rainy, and flood events. Electrical Conductivity (EC), pH, temperature, calcium (Ca2+) and bicarbonate (HCO3
−) were measured directly in the field, while other major elements such as Mg2+, Na+, K+, SO4
2−, Cl− were analyzed in the laboratory. Furthermore, the calculation of the Saturation Indices with respect to the calcite mineral (SIcal) and carbon dioxide partial pressure (logPCO2) was carried out. The analysis results show that temporally, the SIcal value is generally higher during low discharge (dry season) and decreased during high discharge (rainy season). When compared, Jumbleng Springs has a stronger relationship between decreased discharge and an increase in SIcal. Meanwhile, the variation of SIcal increase (during the dry season) is also followed by a decrease in log PCO2, which indicates the dominance of the calcite precipitation process when the carbon dioxide content in the water is minimal.
Flood hydrograph parameters in the Pindul underground river, Gunungkidul, to characterise the release of stored water from karst aquifers
Authors: Tastian N F , Adji T N , Cahyadi A
Published: September 2022

This research was conducted in the Pindul underground river, a cave tubing tourism site in Gunungsewu Karst, Indonesia. The purpose of this study is to identify flood hydrograph parameters that can be used to characterise how karst aquifer release groundwater storage. The recording of water level fluctuations was carried out with the installation of HOBO U20L-02 (November 2020-August 2021). The discharge measurement was carried out 20 times to create a stage-discharge rating curve. Furthermore, eleven flood events were selected to calculate the recession constant of diffuse (Kb), fissure (Ki), conduit (Kc), time to peak (Tp), and time to baseflow (Tb). The results of the calculation of the hydrograph parameters show the number Kb=0.996, which indicates the slow release of groundwater storage supported by the Tb value = 20.72 hours (long enough). Compared with Kb and Tb values in other karst springs in Java, the Pindul underground river has a slightly slower than average releasing of groundwater storage, although its Tb value is shorter than the average for other karst springs. Meanwhile, based on the Kc value (0.429), the Pindul underground river is faster in releasing its conduit flow which is strengthened by a reasonably short Tp data (3.1 hours).
Assessment of Aquifer Systems for The Sustainable Development of Groundwater Use in The Batutua Groundwater Basin
Authors: Syafarini Hane , Hendrayana Heru , Winardi Sarju
Published: September 2022

Groundwater exploration is an alternative to meet raw water needs because of the increasing water demand and the dwindling surface water availability. Water use continues to increase along with the rate of population growth in the Rote Ndao Regency. Therefore, an initial assessment of the presence of groundwater can be carried out by identifying the groundwater basin area. Batutua is one of the groundwater basin areas occupied by the most population because it is the capital of Rote Ndao Regency. This study aims to identify aquifer systems and flow patterns as the basis for groundwater exploration in the Batutua groundwater basin area. The method used in this groundwater aquifer system study is the Vertical Electrical Sounding (VES) method. The VES method is a geoelectrical method used to investigate the layers of an aquifer by interpreting the current that penetrates the soil using two electrodes and the potential response. Geoelectrical investigations were carried out at 8 points in the Batutua groundwater basin area. The aquifer is found in water-containing coral limestone areas where water flows through fractures as secondary permeability. The groundwater flow direction was obtained by measuring the groundwater levels in 14 dug wells and 24 springs. The research’s area aquifer system is formed by upper shallow aquifer as an unconfined aquifer with a thickness less than 20 m and lower shallow aquifer as a semi-confined aquifer that has clay or marls on upper layer and limestone in below with the flow direction from the East to the West and the North part of the study area.
Flood water hydrogeochemistry characteristics in Pindul Cave, Gunungsewu Karst Area, Indonesia
Authors: Tastian N F , Adji T N , Cahyadi A
Published: September 2022

Pindul cave located in Gunungkidul Regency, Gunungsewu Karst Area, Indonesia has a unique characteristic which is dominated by surface rivers (allogenic recharge) and groundwater (autogenic recharge). The main purpose of this study is to analyze temporal variation of flood water hydrogeochemistry in Pindul Cave. Water sampling for flood hydrogeochemistry analysis is taken in the wet season for three selected flood events. Parameters of hydrogeochemistry analysis consist of major dissolved element (Ca2+ and HCO3
−); conductivity; total dissolved solid; SI calcite; log PCO2; and pH. The result shows that there was correlation between flood discharge and hydrogeochemistry parameters. The hydrogeochemistry of flood events in Pindul Cave typified by a low value of calcium and bicarbonate and high CO2 gas content in water that indicated the dillution by precipitation processes. Pindul Cave also show the negative value of calcite during flood event which mean that groundwater is unsaturated, so it becomes aggressive towards calcite. According to the flood water hydrogeochemistry characteristics, Pindul Cave is dominated by conduit flow from the large-fracture that already developed.
Aquifer connectivity assessment using stable isotope and hydrochemical analysis in the Raimanuk and its surrounding area on the Timor island
Authors: Bukhari A M W , Hendrayana H , Setiawan H
Published: September 2022

Raimanuk and its surroundings are a potential agricultural area in Indonesia. Sufficient groundwater in this area was a significant factor for supporting agricultural activities and household needs. Therefore, identifying the aquifer connectivity is essential to determine the groundwater utilization pattern in this area. This research aims to determine the aquifer connectivity based on stable isotopes and hydrochemical from the groundwater and the meteoric water (rainwater). The groundwater samples were taken from ten deep wells, six dug wells, and four springs. While the meteoric water samples were taken from four rainfed locations, samples were analyzed using Los Gatos Research DLT-100, Ion Chromatography Metrohm 830IC, and acid-base titration. The result shows there are four groups of groundwater. Group I is the springs that come from local meteoric water. Group II consists of the dug wells that evaporated and showed a relationship to the meteoric water that falls in higher elevations. Group III was the drilled well groundwater from the local flow system. Furthermore, Group IV is the drilled well groundwater with a more enriched δ18O isotope ratio due to water-rock interaction. Even though they are in a different group, there is a hydraulic connection between Group III and IV.
Analysis of meteorological water availability and water demand in Semarang Regency
Authors: Herdiansyah A R , Zahra R A , Masjoyo Y M , Muhammad A F , Saputra M R , Firdauzi L B , Hafizha K P , Nurjani E
Published: September 2022

Population growths are increasing the demand for water. This can cause an imbalance of water availability to fulfill domestic water demand. Therefore, it is necessary to analyze the water availability and water demand so that water resources are maintained and can fulfill the community needs in the present and future. This research aims to analyze the water availability and domestic water demand in Semarang Regency. The methods consist of calculating monthly rainfall, calculating water balance using F. J Mock model, calculating the water demand regarding to the water availability, and calculating how much water can be obtained from rain harvesting. The results show the highest annual water availability in Semarang Regency is Pringapus district 48,559,764.55 m3/year, while the the lowest is Kaliwungu district 17,352,024.13 m3/year. The highest domestic water demand are in West Ungaran district, East Ungaran district, and Bergas district, while the lowest are in Bancak and Kaliwungu district. The total water demand is 6% of the total water availability, means there is no water deficit in Semarang Regency. The total volume of rainwater harvested is 120,163,412 m3/year which means the volume of rainwater harvested in one year can fulfill the domestic water demand in Semarang Regency.