Original Field Research Articles

Combined application of passive and active boundary layer aspiration in a transonic compressor rotor for shock wave/boundary layer interaction control

Shock wave/boundary layer interaction (SWBLI) is one of the key factors that limits the improvement of aerodynamic performance and stability for supersonic/transonic compressors. In this research, a combined flow control device (CFCD) was designed for controlling SWBLI in the NASA transonic compressor Rotor 35. The original flow fields for Rotor 35 were numerically analyzed first. The results show that the SWBLI is severe, resulting in much flow loss and partly leading to the compressor instability. Based on this phenomenon, the CFCD was designed with a novel three-dimensional passive self-recirculation flow channel and an active suction slot. The flow channel is mounted on the rotor blade suction surface to connect the low- and high-pressure regions ahead of and behind the shock, respectively. The effect of the CFCD on the rotor performance and corresponding working mechanism are then researched as well. With the help of CFCD, the rotor-achieved total pressure ratio (TPR) is maximally increased by 3.0%, and the stall margin (SM) is improved by 4.1% as well. But the rotor isentropic efficiency (IE) considering additional energy expenditure caused by active suction flow has the maximum increment at choke point of 0.27% and highest reduction at near-stall point of 0.54%. The working mechanisms of CFCD include two aspects: one is forming a stable and low-entropy generated lambda shock wave and the other one is reducing the magnitude of flow separation. The dominant mechanism varies with the rotor working condition and depends on whether the leading-edge shock moves upstream of the passive bleed slot.

Magnetic field evolution around a fast-moving pore emerging from the quiet Sun

Context. Solar pores are intense concentrations of magnetic fields on the solar surface and plasma flows have always played a key role in spurring the evolution of the pores. Aims. In this study, we present the evolution of the magnetic field and plasma velocity around a fast-moving pore. The target pore expands into the quiet Sun area with a sufficiently fast speed after its emergence, while the background magnetic fields around the pore are simple. These characteristics provide us with an excellent opportunity to study the interaction between plasma motions and ambient magnetic fields. Methods. We analyzed the Helioseismic and Magnetic Imager (HMI) vector magnetograms with a pixel size of 0.5″ and a temporal cadence of 12 min across a duration of 11 h. We also adopted he HMI dopplergrams present the line-of-sight velocities. The horizontal flow fields were obtained using the Differential Affine Velocity Estimator for Vector Magnetograms method. Results. Pure horizontal magnetic fields are generated in the moving frontwards when the pore is subject to fast movement. The generated magnetic fields occur outside the emerging site and thus can be ruled out as the emerging flux from the interior. Instead, they are highly correlated with the broader downflows and expanding horizontal plasma motions in front of the pore. A magnetic gap can be observed between the magnetic fields inside and outside the pore. The temporal evolution of the generated magnetic fields is related to the speed of the pore, which is also distinguished from the original fields within the pore. Conclusions. The observations suggest that the plasma flows driven by the fast proper motion of the pore compress and stretch the local magnetic field to a horizontal non-radial direction, ultimately leading to the magnetic field amplification in the front part of the moving pore.

Cosmic Tidal Reconstruction with Halo Fields

Abstract The gravitational coupling between large-scale perturbations and small-scale perturbations leads to anisotropic distortions of the small-scale matter distribution. The measured local small-scale power spectrum can thus be used to infer the large-scale matter distribution. In this paper, we present a new tidal reconstruction algorithm for reconstructing large-scale modes using the full three-dimensional tidal shear information. We apply it to simulated dark matter halo fields and find the reconstructed large-scale density field correlates well with the original matter density field on large scales, improving upon the previous tidal reconstruction method, which only uses two transverse shear fields. This has profound implications for recovering lost 21 cm radial modes due to foreground subtraction and constraining primordial non-Gaussianity using the multitracer method with future cosmological surveys.

Argon force field revisited: a molecular dynamic study

We report the improvement of five argon force fields by scaling Lennard-Jones 6–12 potential (LJP) energy (ϵ) and distance (σ) parameters to reproduce liquid-vapor phase diagram and surface tension simultaneously, with molecular dynamics. Original force fields reproduce only liquid-vapor phase diagram among other properties except surface tension. Results showed that all new force fields obtained by scaling LJP parameters reproduce well the experimental surface tension and the liquid-vapor phase diagram, also the LJP energy and distance parameters converge in a nearby region in the ϵ-σ phase space, which is different from the original values. This study gives the intervals where the numerical values of ϵ and σ reproduce both properties mentioned above. Furthermore, a study to calculate surface tension to avoid finite size effects is shown.

Phonon-dressed states in an organic Mott insulator

In an electronic system of solids excited by a femtosecond laser pulse, new quantum states called photon-dressed states are created via the coupling of original electron wavefunctions and periodic electric fields of light. The study of photon-dressed states is a central issue in nonlinear optical science, as a coherent response associated with a photon-dressed state can cause ultrafast optical-switching phenomena. In general, however, phase-sensitive dynamics of photon-dressed states are difficult to observe due to their short lifetime. Here, we show that excitation of the organic Mott insulator potassium-tetracyanoquinodimethane with a strong mid-infrared pulse induces a couple of intramolecular vibrations, which add temporally periodic potentials to the electronic system, giving rise to phonon-dressed states in the picosecond time domain. Through sub-cycle spectroscopy using a phase-stable mid-infrared pulse as an excitation and an ultrashort visible pulse as a probe, we observe optical radiation consisting of four kinds of coherent oscillations with double, sum, and differential frequencies of two intramolecular vibrations. The probe-energy dependence of each oscillation can be well interpreted with phonon-dressed states in the framework of Floquet theory. These findings open a possibility for Floquet engineering in correlated electron materials with strong charge–phonon couplings.

ПОЛЕВЫЕ ИССЛЕДОВАНИЯ ОТДЕЛА РЕЛИГИОВЕДЕНИЯ ИНСТИТУТА ЭТНОЛОГИЧЕСКИХ ИССЛЕДОВАНИЙ УФИМСКОГО ФЕДЕРАЛЬНОГО ИССЛЕДОВАТЕЛЬСКОГО ЦЕНТРА РАН

This article briefly examines the history of field research by the Department of Religious Studies of the Institute of Ethnological Research of the Ufa Federal Research Center of the Russian Academy of Sciences. The Department of Religious Studies has conducted and is currently successfully implementing studies of various aspects of the functioning of Muslim, Orthodox, Protestant and Catholic religious organizations located both in the Republic of Bashkortostan and in the South, Middle and Polar Urals and Western Siberia; ethno-demographic, doctrinal and ideological characteristics of believers are being studied. New empirical and theoretical propositions based on the results of the original field research of the department employees are introduced into the scientific circulation; new scientific problems are revealed, new methods of collection, processing and analysis of empirical materials are being developed. The Department of Religious Studies has achieved fruitful cooperation with the largest religious organizations of both the Republic of Bashkortostan and the Russian Federation.

Coping with shocks: How Self-Help Groups impact food security and seasonal migration

Combining seven years of household data from an original field experiment in villages of Jharkand, East India, with meteorological data, this paper investigates how Indian Self-Help Groups (SHGs) enable households to withstand rainfall shocks. I show that SHGs operate remarkably well under large covariate shocks. While credit access dries up in control villages one year after a bad monsoon, reflecting strong credit rationing from informal lenders, credit flows are counter-cyclical in treated villages. Treated households experience substantially higher food security during the lean season following a drought and increase their seasonal migration to mitigate expected income shocks. Credit access plays an important role, together with other SHG aspects such as peer networks. These findings indicate that local self-help and financial associations can help poor farmers to cope with climatic shocks and to implement risk management strategies.

The Extractive Industries Transparency Initiative (EITI) and local institutions in Ghana’s mining communities: Challenges in understanding barriers to accountability

SummaryMotivationThe Extractive Industries Transparency Initiative (EITI) is a global standard that promotes transparency and accountability in resource‐rich countries to improve governance of the extractive sector. Despite improvements in the subnational disclosure of royalty payments, a significant problem is the failure of these efforts to improve accountability and benefits to mining communities.PurposeThe article asks how institutions of local governance affect national efforts to improve accountability to mining communities in Ghana on the use of mineral revenues for development. It contributes to the broader theoretical literature on EITI by clarifying what outcomes, if any, can be directly attributed to the disclosure of royalty payments.Methods and approachThis qualitative study employs a case‐study analysis of EITI adoption in Ghana, one of the first countries to join the initiative. The article contextualizes local governance institutions and dynamics in relation to the royalty disbursement process. It draws on original field research to analyse their role in impeding the expected benefits of royalty disbursements to mining‐affected communities.FindingsThe research identifies deficiencies in local governance structures and processes as they relate to the use of mineral royalties, but also instances of variation in how officials react to EITI. The range of individual actors, institutions, and complex processes on which the subnational disbursement of royalties depends, makes it problematic to attribute the absence of improvements directly to Ghana's EITI. The findings demonstrate that EITI's role in participating countries is best understood as facilitative and indirect when addressing development outcomes for mining communities.Policy implicationsDisclosure of royalty payments to local governments is unlikely on its own to result in improved development outcomes for local communities, even when the national government is committed to the goal. There is a need for policy interventions aimed at specific communities to ensure royalty payments reach the intended beneficiaries. These interventions should be tailored to the differences in national governance dynamics in countries participating in EITI, paying attention to contestation over the distribution and expenditure of royalties that disclosure helps bring to light.

The new, LADM inspired, data model of the Dutch cadastral map

The Netherlands’ Cadastre, Land Registry and Mapping Agency – in short Kadaster – provides legal certainty about every piece of land (and water) in the Netherlands. Newly surveyed cadastral boundary geometry is documented in land surveying field sketches and processed in the nationwide cadastral map. Because of the different working methods since the start of cadastral surveying in 1811 (a nationwide cadastral map was available in 1832 when Kadaster was established) the map has a so-called graphical quality. The standard deviation of boundary points is 20 cm for urban areas and 40 cm for rural areas (in the national reference system), this implies that the geometric quality of the current map is insufficient for determining the exact parcel location in the field. With an increasing digitization and open data policy, multiple sources of information (including the cadastral map) are demanded to be accessible and usable by a wide range of users. This so-called geographical quality and its limitations leads to bottlenecks and incomprehension. This is the reason why Kadaster has started a program, the Cadastral Map Next program, aiming at the development of a methodology for the development of a new version of the cadastral map. The aim of this new version is that the location of boundaries is so accurate, that the boundary coordinates from the map are usable for a better approximation of the boundary location in the field and can accommodate future demands and developments. This development process is based on the use of the original field observations. For this purpose, almost all observations on all (historical) field sketches must be processed. There are about 5 million digitally archived field sketches. This is an enormous challenge that requires far reaching automation. The program has investigated whether it is possible to automatically extract the original (mostly handwritten) measurements from the field sketches and to combine this information and re-determine the location of the boundaries with a very high accuracy of boundary points. With the support of several companies, it has been possible to build a cadastral map with a known geometrical quality and verified accuracy. This accurate cadastral map is called ‘Reconstruction Map’, a working title for the cadastral map with known geometrical quality and higher accuracy. Once this map is ready and the involved parties agree, it will be introduced and presented as the ‘Cadastral Map Next’ and replace the current cadastral map. An important step in this process is to redesign the current data model from parcel level to the more specific boundary level to achieve an unambiguous connection between cadastral objects and its related survey data. A challenge in this process is that the current survey documents only describe changes in a parcel, thus different boundaries of a parcel are related to different survey documents. This challenge should be addressed in the new model. The new data model applies the sub-package ‘Survey and Representation’ of the Land Administration Domain Model (LADM), an ISO standard, for solid solutions in their design process. The basic structure of spatial sources, points, boundaries and parcels, all with their own identification, enables to store relevant data, like coordinates, quality descriptions and metadata, as attributes to these objects. Further new relations can be established while previous ones are maintained. The concept of the ‘Reconstruction Map’ and the ‘information layer’ (metadata) will bring new insights to establish new relations and so relate the different cadastral objects in a more dedicated way.

On the structural description of random fields

The article considers an approach to the description of random fields as a set of intense structures with random parameters. Such structures are observed both in optical fields propagating in inhomogeneous media and fields of hydrodynamic origin and are formed because of focusing on radiation or deformation of flows. The article discusses the filtration methods and the evolution of such structures. Different modes of structures, modes of periodic and stochastic oscillations, are described.

Diversity of academic general medicine: A cross-sectional bibliometric study of original English-language research articles in general medicine and cardiology in Japan.

Although research in general medicine is diverse, it has not been compared with research in a different medical specialty. The study aim was to understand the characteristics of research produced at Japanese university departments of general medicine and published in English-language journals, via comparison with another academic specialty, cardiology.In this cross-sectional study, a nationwide survey of the official websites of 82 university-affiliated medical schools in Japan was conducted in April 2020 to identify the heads of general medicine departments. We then surveyed the research output of these individuals in terms of original article output and research field diversity for journals listed in the Web of Science Core Collection of journals from 2010 to 2019. A similar survey of cardiology department publications was also conducted to provide a reference for intergroup comparisons and analysis of covariance.The analysis included 128 researchers from 78 general medicine departments and 96 researchers from 81 cardiology departments. The dominant research field of general medicine was general and internal medicine; that of cardiology was cardiac/cardiovascular systems. Data stratification by research field showed that general medicine researchers published significantly more articles than researchers in cardiology, a field that contains relatively few researchers. Furthermore, a comparison of individual researchers with the same number of published articles showed that researchers in general medicine departments published across a significantly wider range of fields than those in cardiology.This is the first study to describe the research characteristics of general medicine university departments in Japan through comparison with research in a different academic specialty. General medicine researchers in Japan comprise a heterogeneous group that mainly publishes research on general and internal medicine. Some general medicine researchers take a multidisciplinary approach to research and publishing.

Velocity Field Level Set Method Incorporating Topological Derivatives for Topology Optimization

Abstract The velocity field level set method constructs the velocity field by velocity design variables and basis functions, and thus facilitates the use of general optimizers while still retaining the level set-based implicit topological representation. This paper incorporates the topological derivative concept into the velocity field level set method to enable automatic nucleation of interior holes. In each design iteration, a specified volume fraction of new holes is inserted at locations with smaller values of topological derivatives. Thus, the method provides a way to directly change the structural topology during the boundary evolution using the velocity field based on the shape sensitivity. Compared with the original velocity field level set method, the current implementation can further accelerate the topological and shape evolution during the optimization process. More importantly, the capability of hole nucleation eliminates the need of prescribing initial holes and thus alleviates the dependency of the optimized design on the initial design. Several numerical examples in both 2D and 3D design domains are presented to demonstrate the validity and efficiency of the proposed method.

Study on the Evolution Law and the Orientation Criterion of a Plastic Zone in Rock Surrounding a Circular Roadway in a Three-Dimensional Non-Isobaric Stress Field

The original rock stress field is mainly divided into the σHZ-dominant stress field, the σZ-dominant stress field, and the σH-dominant stress field. Via theoretical analysis, the plastic zone morphology and the orientation of roadway surrounding rock under a three-dimensional stress field are studied in depth, and the theory is verified by numerical simulation. The results show that in the σHZ-dominant stress field, the plastic failure mode changes from elliptical to quasi-circular to butterfly, and the optimized angle range of the roadway orientation is determined by three principal stresses. In the σZ-dominant stress field, the shape of the plastic zone transforms from butterfly to ellipse, the optimized angle range of the roadway orientation is 50–90°, and the butterfly hidden danger zone is in the 0–50° range. In the σH-dominated stress field, the shape of the plastic zone transits from ellipse to butterfly. The optimized angle range of the roadway orientation is 0–40°, and 50–90° is the butterfly hidden danger zone.

A field cooling method to increase the suspension force of HTS pinning maglev system

High-temperature superconducting (HTS) pinning magnetic levitation (maglev) transit, with the advantages of passive stabilization, nearly resistance free and the ability to suspend in different directions, has attracted more and more attentions. Though the USF (upper-suspension form) and SSF (side-suspension) form of HTS pinning maglev were widely studied and gradually applied in engineering, the weak loading capacity of the LSF (lower-suspension form) has been keeping it from application. In this paper, a new field cooling method is proposed to increase the suspension force of the HTS pinning maglev system in LSF. The vertical and lateral suspension force using the new proposed method was measured and analyzed by two rectangular three-seeded YBa2Cu3O7 bulks, as well as the LSF with the original field cooling method and the USF for comparison. The result shows that, when the bulks move down in 5 mm, the vertical suspension force reaches to 207 N when the FCG (field cooling gap) is 5 mm, 70 N when the FCG is 15 mm. The experimental data suggests that the new proposed field cooling method can increase the vertical suspension force by 32%, and also increase its stability. With this new field cooling method, the loading capacity of the LSF can almost reach the USF, while the guiding capacity is far better than the USF. This paper suggests that the LSF is a potential suspension form for the HTS pinning maglev with the new proposed field cooling method. And this paper can provide insight and reference for different HTS pinning suspension form.

Caring for biosocial complexity. Articulations of the environment in research on the Developmental Origins of Health and Disease

The research field of Developmental Origins of Health and Disease (DOHaD) provides a framework for understanding how a wide range of environmental factors, such as deprivation, nutrition and stress, shape individual and population health over the course of a lifetime. DOHaD researchers face the challenge of how to conceptualize and measure ontologically diverse environments and their interactions with the developing organism over extended periods of time. Based on ethnographic research, I show how DOHaD researchers are often eager to capture what they regard as more ‘complex’ understandings of the environment in their work. At the same time, they are confronted with established methodological tools, disciplinary infrastructures and institutional contexts that favor simplistic articulations of the environment as distinct and mainly individual-level variables. I show how researchers struggle with these simplistic articulations of nutrition, maternal bodies and social determinants as relevant environments, which are sometimes at odds with the researchers’ own normative commitments and aspirations.

Epigenetics in the Anthropocene: an interview with Oskar Karlsson.

In this interview, Oskar Karlsson speaks with Storm Johnson, commissioning editor for Epigenomics, on his work to date in the field of toxicological origins of disease and gene-environment interactions. Oskar Karlsson, is an associate professor at the Science for Life Laboratory (SciLifeLab), Department of Environmental Science, Stockholm University, Sweden. Dr. Karlsson earned a PhD in toxicology at the Department of Pharmaceutical Bioscience, Uppsala University, and has also worked at Centre of Molecular Medicine, Karolinska Institute, as well as Harvard UniversitySchool of Public Health. His research combines experimental model systems, computational and omics tools, and epidemiological studies to investigate the influence of environmental exposures on wildlife and human health, and underlying molecular mechanisms. In particular, his research focuses on developmental origins of health and disease with an emphasis on environmental exposures and epigenetic mechanisms. The projects concern the effects of exposures such as endocrine disrupting chemicals, flame retardants, pesticides, metals andparticulate air pollution, as well as drugs, psycho-social stressorsand ethnical disparities. Ongoing efforts include studies of paternal epigenetic inheritance in the ERC-funded project PATER.

The Use of an Equivalent Temperature Field to Emulate an Induced Residual Stress Field in a Rotating Disk Due to Full Or Partial Rotational Autofrettage

Abstract The evaluation of equivalent temperature fields for cylindrical and spherical pressure vessels to imitate autofrettage induced residual stresses has been successfully implemented in studying crack growth in autofrettaged vessels by the finite element method. Rotational autofrettage is a recent method that can be employed for strengthening hollow disks used in many turbomachinery. The evaluation of the equivalent temperature field becomes pivotal in the performance assessment of autofrettaged cracked disks subjected to high rotational speed. In this work, an equivalent thermal loading method for emulating the residual stress field in a hollow rotating disk, induced by full or partial rotational autofrettage in a finite element analysis is suggested. An analytical, or a numerical discrete solution, evaluating the equivalent temperature field for an arbitrary axisymmetric residual stress field, induced in a rotating disk due to rotational autofrettage, is developed. This solution is implemented in a finite element analysis to emulate the original rotational autofrettage induced residual stresses in a typical rotating disk. Applying the equivalent temperature field, the residual stresses obtained in the finite element analysis, are further corroborated with the original residual stress field introduced by rotational autofrettage. It is found that the developed equivalent temperature fields excellently reproduce the residual stress fields, within less than 1%, induced by both full or partial rotational autofrettage.

What drives forest rule compliance behaviour in the Congo Basin? A study of local communities in Cameroon

Forest law compliance can play an important role in enhancing natural resource governance and advancing sustainable development. The role of compliance and the factors that affect it require better consideration in the planning and implementation of international forest policies. This study presents an analysis of factors that influence forest law compliance behaviour among local communities in Cameroon. The analysis is based on forest communities’ self-reported compliance with two forest rules in Cameroon, both of which are part of formal state forestry law. Original field data from 151 individual respondents in 6 villages located in easter and south-eastern Cameroon are analysed using logistic regression analysis. We find that several instrumental, normative, legitimacy and contextual factors affect the forest law compliance behaviour of local communities. A number of factors, including the perceived probability of detection and sanctions (instrumental), tradition/religion (normative), participatory rule making (procedural legitimacy) and property rights (contextual and governance related factors) are found to significantly influence local communities’ forest rule compliance behaviour. Our findings carry implications for the design and implementation of existing and future forest policies and interventions to manage forest resources sustainably in many parts of the world.

Location of the Lhasa terrane in the Late Cretaceous and its implications for crustal deformation

The Cenozoic crustal deformation of the Asian continent is constrained by the location of its southern margin in the Late Cretaceous, which is, however, affected by potential remagnetization and inclination shallowing of redbeds in the Linzhou Basin. Our paleomagnetic results from the Shexing Formation redbeds in the Late Cretaceous yield a mean paleo-inclination of ~21.5°, consistent with the recalculation of previous data. Rock-magnetic, paleomagnetic and petrographic analyses indicate that the redbeds have recorded the original paleomagnetic field and have not suffered from significant inclination shallowing. The paleopole from 70 redbeds sites is at 71.8°N, 281.5°E with A 95 = 2.6°, yielding a paleolatitude of ~12.0 ± 2.6°N at ~70–91 Ma for the Linzhou Basin. This result indicates a latitudinal convergence of 1264 ± 477 km north of the sampling area within Asia since the Late Cretaceous. Combined with previous data, our results show that the southern margin of Asia was at ~11–15°N in the Late Cretaceous, aligning in a WNW-ESE direction, which is similar to its present-day orientation. A review of available data shows that the sharp bending of the southern margin of Asia around the eastern Himalayan syntaxis (EHS) is probably due to different crustal movement patterns around the EHS. The shape of the southern margin of Asia determines the arc-shaped orientation of Himalayan orogen. • The Shexing Formation redbeds have recorded the prefold magnetizatioin. • The southern margin of Asia was oriented in a WNW-ESE direction at ~12°N. • Different movement around the eastern Himalayan syntaxis make a sharp turn. • The southern margin of Asian plays a primary role in shaping the Himalayan orogen.

The geology of the Western Alps through the field notebooks of Secondo Franchi (1859-1932)

Secondo Franchi (1859–1932) was one of the most important geologists of the Regio Ufficio Geologico of Italy. In collaboration with his colleagues of the Turin office, starting from 1888 Franchi surveyed in detail the Western Alps to contribute to the new Geological Map of Italy at the 1:100,000 scale. Franchi’s studies contributed to the definition of a still largely accepted chronostratigraphic framework for the Alpine successions, and to the recognition of previously overlooked folding and faulting phases in the Western Alps. Eleven of Franchi’s field notebooks are kept in the Library of Istituto Superiore per la Protezione e la Ricerca Ambientale in Rome. These notebooks are richly illustrated with geological sections and landscape sketches and represent an invaluable first- hand resource for the analysis of Franchi’s mapping methods and interpretive procedures. This paper analyses Franchi’s contribution to the geological knowledge of some specific localities of the Western Alps, integrating excerpts from his original field notebooks and published works.