Spatial Orientations Research Articles

Combined Use of 2 Cone-beam Computed Tomography Scans in the Assessment of Vertical Root Fracture in Teeth with Intracanal Material

IntroductionThe purpose of this preliminary study was to evaluate the diagnostic accuracy of the combined use of 2 cone-beam computed tomographic (CBCT) volumes obtained with the tooth of interest positioned at different orientations in the detection of vertical root fracture (VRF). MethodsThirty single-rooted teeth were divided into 2 main groups (n = 15): control and with VRF. The teeth were individually placed in a phantom composed of a human skull and mandible, which was CBCT scanned in 2 spatial orientations: conventional (with the Frankfurt plane parallel to the floor) and angled acquisition (tilted 90° backward). Also, each tooth was scanned with gutta-percha, a metal post, and without any intracanal material. Three oral radiologists individually evaluated the images resulting from conventional acquisition and verified the presence or absence of VRF (conventional CBCT assessment), setting a score on a 5-point scale. Subsequently, the observers evaluated both images resulting from the conventional and angled acquisitions (combined CBCT assessment). The diagnostic values of the conventional and combined assessments were compared using 2-way analysis of variance with the post hoc Tukey test. The significance level was set at 5% (α = 0.05). ResultsThe combined CBCT assessment showed higher accuracy and sensitivity in the VRF diagnosis of teeth filled with gutta-percha (P < .05). In teeth with a metal post, all diagnostic values were higher in the combined CBCT assessment (P < .05). ConclusionsThis preliminary study suggests that the CBCT-based diagnosis of VRF in teeth with intracanal material was improved when the assessment combines images obtained at 2 orientations.

Sexuality politics on the football field: queering the field in Turkey

AbstractFocusing on queer-identified amateur football teams, this article investigates the potentials of the mobilities and alliances of gender non-conforming footballing people to disrupt the seemingly effortless structure of the football field. While football is arguably one of the sports with the strongest discriminatory attitudes toward gender non-conforming people, it has also become a site of resistance for queers in Turkey as of 2015. How political opposition groups relate to the football field, which is mostly considered as a male-dominant and heterosexualized space where social norms are reproduced, are classified into three groups in my research: resistance through, against, and for football. I give particular attention to the category “resistance for football” as a distinctive way for gender non-conforming people to inhabit the field. I discuss how the link between sexual and spatial orientations shapes the domain of what a body can do, both in terms of normativity and capacity, and I explore what these teams offer in order to exceed spatial and sexual boundaries. Lastly, I present recent queer interventions in the value system of the game through which I reflect upon the concept of “queer commons” and the processes of bonding, belonging, and border-making in queer communities.

Изучение динамических процессов в задачах сейсморазведки пластов мезотрещиноватости методами математического и физического моделирования

The article is devoted to the study of the propagation of elastic waves in a fractured seismic medium by methods of mathematical modeling. The results obtained during it are compared with the results of physical modeling on similar models. For mathematical modeling, the grid-characteristic method with hybrid schemes of 1-3 orders with approximation on structural rectangular grids is used. The ability to specify inhomogeneities (fractures) of various complex shapes and spatial orientations has been implemented. The description of the developed mathematical models of fractures, which can be used for the numerical solution of exploration seismology problems, is given. The developed models are based on the concept of an infinitely thin fracture, the size of the opening of which does not affect the wave processes in the fracture area. In this model, fractures are represented by boundaries and contact boundaries with different conditions on their surfaces. This approach significantly reduces the need for computational resources by eliminating the need to define a mesh inside the fracture. On the other hand, it allows you to specify in detail the shape of fractures in the integration domain, therefore, using the considered approach, one can observe qualitatively new effects, such as the formation of diffracted waves and a multiphase wavefront due to multiple reflections between the surfaces, which are inaccessible for observation when using effective fracture models actively used in computational seismic. The obtained results of mathematical modeling were verified by physical modeling methods, and a good agreement was obtained.

Computational study of inversion‐topomerization pathways in 1,3‐dimethylcyclohexane and 1,4‐dimethylcyclohexane: Ab initio conformational analysis

AbstractThis work concerns the special conformational behaviors for di‐substituted cyclohexanes that inherently depend on spatial orientations of side chains in flexible cyclic ring. The 1,3‐dimethylcyclohexane and 1,4‐dimethylcyclohexane in both cis‐ and trans‐configurations were focused here to unravel their inversion‐topomerization mechanisms. Full geometry optimizations were separately performed at B3LYP/6‐311++G(d,p) and MP2/6‐311++G(d,p) levels to explicitly identify all distinguishable molecular structures, and thereby the complete interconversion routes were carefully explored. Additional quantum calculations were carried out by G4 and CCSD(T)/6‐311++G(d,p) methods to acquire high‐level single point energies. With respect to quantum results, conformational analysis was conducted to study determinations, thermodynamic stabilities, and relative energies of distinct conformers. Temperature‐dependent populations of local minima for each dimethylcyclohexane were computed by Boltzmann distribution within 300–2500 K. Moreover, their unique inversion and topomerization processes were fully investigated, and potential energy surfaces were illustrated with the rigorous descriptions in two or three‐dimensional schemes for clarify.

Spatial Language of Young Children During Block Play in Kindergartens in Urban China.

Spatial language is an important predictor of spatial skills and might be inspired by peer interaction and goal-oriented building behaviors during block play. The present study investigated the frequency, type and level of children’s spatial language during block play and their associations with the level of block play by observing 228 young children in classrooms equipped with unit blocks and allowing free play on a daily basis. The findings showed that during block play, young children used more words about spatial locations, deictic terms, dimensions, and shapes and fewer words about spatial features or properties and spatial orientations or transformations. Spatial locations were used most frequently, and young children tended to use vertical location words to represent the corresponding location. Most young children used gestures in conjunction with spatial deictic terms. Among shape words, tetragon words were frequently used, and the representation of spatial shapes showed alternatives, collective tendencies and gender differences. The use of spatial language during the play process had a significant positive correlation with age, the construction structure, and form of block building.

Sign language digits and alphabets recognition by capsule networks

There exist communication barriers between the deaf people and the listeners. Sign language translation is a reasonable and effective way to break these barriers. Recognition of sign language symbols is an essential part of sign language translation. Sign language digits of (0–9) and alphabetic letters of (A–Z) are elementary but important symbols of sign languages of different countries or regions. Capsule networks (CapsNet) are promising alternative to convolutional neural networks (CNN), which take into account of the spatial relationships and orientations of the features of an entity. For sign language digits and alphabets recognition tasks, the proposed SLR-CapsNet architecture achieves a start-of-the-art test accuracy of 99.52% with 100*100 RGB input size and 99.94% with 32*32 RGB input size on Sign Language Digits Dataset and 99.60% with 28*28 Gray-scale input on Sign Language MNIST Dataset. The experimental results also prove that CapsNet has higher generalization and expressiveness capacity on unseen data than CNN dose. Another important finding in our work is that SLR-CapsNet is robust to routing iterations, i.e., its performance will not be affected by various routing iterations.

Molecular docking, binding mode analysis, molecular dynamics, and prediction of ADMET/toxicity properties of selective potential antiviral agents against SARS-CoV-2 main protease: an effort toward drug repurposing to combat COVID-19.

The importance of the main protease (Mpro) enzyme of SARS-CoV-2 in the digestion of viral polyproteins introduces Mpro as an attractive drug target for antiviral drug design. This study aims to carry out the molecular docking, molecular dynamics studies, and prediction of ADMET properties of selected potential antiviral molecules. The study provides an insight into biomolecular interactions to understand the inhibitory mechanism and the spatial orientation of the tested ligands and further, identification of key amino acid residues within the substrate-binding pocket that can be applied for structure-based drug design. In this regard, we carried out molecular docking studies of chloroquine (CQ), hydroxychloroquine (HCQ), remdesivir (RDV), GS441524, arbidol (ARB), and natural product glycyrrhizin (GA) using AutoDock 4.2 tool. To study the drug-receptor complex's stability, selected docking possesses were further subjected to molecular dynamics studies with Schrodinger software. The prediction of ADMET/toxicity properties was carried out on ADMET Prediction™. The docking studies suggested a potential role played by CYS145, HIS163, and GLU166 in the interaction of molecules within the active site of COVID-19 Mpro. In the docking studies, RDV and GA exhibited superiority in binding with the crystal structure of Mpro over the other selected molecules in this study. Spatial orientations of the molecules at the active site of Mpro exposed the significance of S1–S4 subsites and surrounding amino acid residues. Among GA and RDV, RDV showed better and stable interactions with the protein, which is the reason for the lesser RMSD values for RDV. Overall, the present in silico study indicated the direction to combat COVID-19 using FDA-approved drugs as promising agents, which do not need much toxicity studies and could also serve as starting points for lead optimization in drug discovery.Graphic abstract

The Mass-loss History of the Red Hypergiant VY CMa*

Abstract Imaging and spectroscopy of the knots, clumps, and extended arcs in the complex ejecta of VY CMa confirm a record of high mass-loss events over the past few hundred years. Hubble Space Telescope/Space Telescope Imaging Spectrograph spectroscopy of numerous small knots close to the star allow us to measure their radial velocities from the strong K i emission and determine their separate motions, spatial orientations, and time since ejecta. Their ages concentrate around 70, 120, 200, and 250 yr ago. A K i emission knot only 50 mas from the star ejected as recently as 1985–1995 may coincide with an H2O maser. Comparison with VY CMa’s historic light curve from 1800 to the present shows several knots with ejection times that correspond with extended periods of variability and deep minima. The similarity of this correspondence in VY CMa with the remarkable recent dimming of Betelgeuse and an outflow of gas is apparent. The evidence for similar outflows from the surface of a more typical red supergiant suggests that discrete ejections are more common and surface or convective activity is a major source of mass loss for red supergiants.

Instructional Approaches: Anatomy Education of Physical Therapists.

The profession of physical therapy has undergone an evolution since its inception. Since the early 1900s it has grown from a technical training program to a doctorate level degree. Human anatomy courses remain a requirement for physical therapist educational curricula. However, changes in anatomy pedagogy have been trending within health profession educational models, leading to questions regarding which method is best for student learning. The objective of this study was to determine if anatomy instructional method used within physical therapist educational curricula impacted current anatomy knowledge. Licensed physical therapists were recruited to complete a demographic survey and a questionnaire to demonstrate their knowledge of anatomy topics. Anatomy topics included six regional components: (1) upper limb; (2) lower limb; (3) thorax and abdomen; (4) pelvis; (5) spine; and (6) head. Each regional component contained five questions regarding systemic subsets related to joints and osteology, muscles, nervous system, vasculature, and special areas (e.g., spatial orientations, structures within spaces, pathways of nerves). Within the thorax and abdominal region, data analysis indicated that the dissection instruction method, when compared to no laboratory instruction, led to statistically significant greater anatomical knowledge (P=0.02). Dissection also showed greater means when compared to the no laboratory method (P=0.02) and the prosection method in the head region (P=0.01). However, the variance explained by instructional method was small. This study adds empirical evidence regarding current anatomy knowledge exhibited by physical therapists as the level of anatomical knowledge exhibited small differences based on instructional methods.

Defining a no-reference image quality assessment by means of the self-affine analysis.

In this paper we propose a novel Blind Image Quality Assessment via Self-Affine Analysis (BIQSAA) method by considering the wavelet transform as a linear operation that decomposes a complex signal into elementary blocks at different scales or resolutions. BIQSAA decomposes a distorted image into a set of wavelet planes ωλ, ϕ of different spatial frequencies λ and spatial orientations ϕ, and it transforms these wavelet planes into one-dimension vector Ω using a Hilbert scanning. From the vector Ω there were obtained their wavelet coefficient fluctuations estimated by the inverse of the Hurst exponent in decibels, whose scaling-law or fractal behavior was obtained by applying Fractal Geometry or Self-Affine Analysis. The scaling exponents calculated for the coefficient fluctuation behavior of Image Lena at 24bpp, at 1.375bpp, and at 0.50bpp were H24bpp = 0.0395, H1.375bpp = 0.0551, and H0.50bpp = 0.0612, respectively. Our experiments show that BIQSAA algorithm improves in 14.36% the Human Visual System correlation, respect to the four state-of-the-art No-Reference Image Quality Assessments.

A Bio-Inspired 3-D Neural Compass Based on Head Direction Cells

Head direction cells (HDCs) in mammals’ brains are thought to provide the sense of direction (function of a compass). They fire when the animal’s head points to a specific orientation. In this paper, a bio-inspired neural compass with 3 degrees of freedom (DOFs) which is consistent with neurophysiological characteristics of biological HDCs in three-dimensional (3-D) environments is proposed. The proposed model, which is based on continuous attractor neural network (CANN), is primarily driven by angular velocity of head turning to determine spatial orientations of unmanned vehicles in 3-D environments. By means of Hebbian learning, external perception information such as visual landmarks can be incorporated to calibrate cumulative errors of path integration based on self-motion information. Experimental results obtained by validating the model on a two-axis motion simulator are given. The neural system enables the simulator to track its spatial orientations in 3-D environments effectively.

Synthetic glycosidases for the precise hydrolysis of oligosaccharides and polysaccharides.

Glycosidases are an important class of enzymes for performing the selective hydrolysis of glycans. Although glycans can be hydrolyzed in principle by acidic water, hydrolysis with high selectivity using nonenzymatic catalysts is an unachieved goal. Molecular imprinting in cross-linked micelles afforded water-soluble polymeric nanoparticles with a sugar-binding boroxole in the imprinted site. Post-modification installed an acidic group near the oxygen of the targeted glycosidic bond, with the acidity and distance of the acid varied systematically. The resulting synthetic glycosidase hydrolyzed oligosaccharides and polysaccharides in a highly controlled fashion simply in hot water. These catalysts not only broke down amylose with similar selectivities to those of natural enzymes, but they also could be designed to possess selectivity not available with biocatalysts. Substrate selectivity was mainly determined by the sugar residues bound within the active site, including their spatial orientations. Separation of the product was accomplished through in situ dialysis, and the catalysts left behind could be used multiple times with no signs of degradation. This work illustrates a general method to construct synthetic glycosidases from readily available building blocks via self-assembly, covalent capture, and post-modification. In addition, controlled, precise, one-step hydrolysis is an attractive way to prepare complex glycans from naturally available carbohydrate sources.

DETERMINATION OF MONOPOLE AND DIPOLE SOURCES OF FLOW AROUND A CYLINDER USING A VIRTUAL MICROPHONE ARRAY

In this paper, the problem of localization of noise sources of flow around a cylinder was considered on the basis of a computational experiment using a virtual 54-channel microphone array. Numerical simulation was performed using the computational fluid dynamics software ANSYS Fluent. Several spatial orientations of the cylinder were considered for the generation of dipoles with different directions. Simulation of a simplified two-microphone azimuthal decomposition technique (ADT) is performed to determine the sound pressure level of the generated dipoles at a vortex shedding frequency of 1450 Hz. A procedure of localization of the noise of the flow around a virtual cylinder was performed using monopole and dipole beamforming algorithms. It was found that the numerical simulation results are in good agreement with the data obtained by other researchers, both in terms of the sound pressure level and the results of the localization of dipoles in space.

São Paulo: A Graphic Biography by Felipe Correa

Reviewed by: São Paulo: A Graphic Biography by Felipe Correa Brian J. Godfrey Felipe Correa São Paulo: A Graphic Biography. Austin: University of Texas Press, 2018. 348 pp. Maps, diagrams, ills., appendices, references. $65 Cloth (ISBN 978-1-4773-1627-6). São paulo, the most populous and extensive megacity in South America, vies with Mexico City and New York as the largest metropolis in the Western Hemisphere. Founded as São Paulo dos Campos de Piratininga in 1554, the city began to grow rapidly with the coffee trade and railroads of the late nineteenth century; it exploded in size with the industrialization, cars, and trucks of the twentieth century. Also striking is the city's spectacular verticalization, evident in some 6,000 highrises that now spread across the urban horizon. Growth has slowed in recent years, however, as São Paulo has faced economic restructuring, traffic congestion, air pollution, aging infrastructures, prolonged [End Page 188] drought, problems of public health, and now the Covid-19 pandemic. Consequently, this is a good juncture to review the origins, growth, spatial structure, environmental issues, and general resilience of this enormous city-region. This substantial volume, authored by architect Felipe Correa, traces the evolving contours of the city's urban form and built environment. Abundantly illustrated with a bilingual text in English and Portuguese, São Paulo: A Graphic Biography includes five major units. The first and by far the longest—comprising two-thirds of the book—is Unit A, São Paulo: Models of Urban Growth. Rather than attempt a single comprehensive model, given the density and complexity of this kaleidoscopic city, Correa opts to visualize and interpret the dominant processes of urban growth. The core of the book focuses on eight topics: City of Ridges and Valleys, City of Citadels, City of Points, City of Spreads and Densities, City of Voids, City of Collective Living, City of Warehouses, and City of Layered Economies. These topical subsections include lively essays by seven other contributors, who supplement Correa's broad appraisals with opinion pieces. Despite the diversity of topics, they all reflect multi-scalar, interdisciplinary, and historical approaches to a dynamic mega-city well worth studying. As Edward Glaeser notes in the foreword, "one great challenge of the twenty-first century is to tame the demons that come with density in cities like São Paulo" (p. 7). There is much to commend in this Graphic Biography. Along with its stylish design, the book is chock-full of thematic maps, archi tectural models, analytical diagrams, and historical and contemporary photographs—all of which parallel and enliven the text. In fact, the reader can quickly get lost in the profusion of graphic delights, but their quantity and diversity mirror the multi-faceted city itself. Lacking the clear physical limits and the orderly ground plans of more legible cities, the Paulista capital aggregates "multiple neighborhoods, each with a unique structure and identity… São Paulo grew as a patchwork of urban developments" (p. 49). A series of street maps included in the book show a dizzying array of spatial orientations, extensions, and curvatures. Indeed, I recall from my urban geography classes a student from São Paulo, whose mental-map exercise––based on Kevin Lynch's Image of the City––stressed the irregular streets and difficulty of getting one's bearings. Correa also points to the city's rapid growth and adoption of "heavyweight hydrological and mobility infrastructure models… disconnected from civic and urban aspirations" (p. 10). The utilitarian infrastructures of highways, railroads, channelized rivers, and other large engineering projects, he argues, disrupt the urban fabric. The resulting morphological fragmentation helps to explain the difficulty even residents can have in orienting themselves. Besides its spatial emphasis, the book examines how the expansive built environment has urbanized and for the most part degraded nature. The channelization of rivers along industrial, transportation, and residential corridors, according to Correa, "has resulted in hydrological projects that in many instances are at odds with the general urbanization [End Page 189] patterns in the city" (p. 25). Renato Anelli discusses the juxtaposition of highways and rivers within narrow metropolitan corridors, which results in seasonal flooding, chronic shortages of...

Spatial orientations of angular momentum vectors of galaxies in Supercluster S [173+014+0082

The spin vector orientation of 1302 SDSS (Sloan Digital Sky Survey) galaxies in Supercluster S[173+014+0082] having redshift 0.076 to 0.091 has been analysed. The positions, position angles and inclination angles of galaxies are used to convert two-dimensional observed parameters into three-dimensional angular momentum vectors of the galaxy using the `position angle-inclination' method. The expected isotropic distribution curves are determined performing numerical simulation by generating 107 virtual galaxies. The observed distribution is compared with the expected isotropic distribution curves using three statistical tools namely Chi-square test, auto-correlation test and Fourier test. Redshift map is studied and found that the distributions fit with the Gaussian. No preferred alignment of angular momentum vectors is noticed, supporting Hierarchy model of galaxy formation.&#x0D; BIBECHANA 18 (2021) 26-32&#x0D;

Spatial orientations of common bean (Phaseolus vulgaris L.) influence the activity and population dynamics of bean stem maggot (Ophiomyia phaseoli) and bean foliage beetle (Ootheca mutabilis)

Common bean (Phaseolus vulgaris L.) is an important legume for food and income for smallholder farmers all over the world. Pests such as bean stem maggot BSM (Ophiomyia phaseoli) and bean foliage beetle BFB (Ootheca mutabilis) pose a serious challenge to production. Many practices have been employed to manage these pests. However, little or no emphasis has been on basic agronomic practices such as plant spacing as a tool for pest management. In the present study, the role of plant orientation (plant spacing) on the activities and population dynamics of BSM and BFB was examined in a pesticide-free field trial in Bamenda, Cameroon from March to July, 2020. Different plant orientations namely 15cm x 15cm (~442500 plants/ha), 20cm x 20cm (~250000 plants/ha), 30cm x 30cm (~110000 plants/ha) and 40cm x 40cm (~62500 plants/ha) were test in a randomized complete block design with 4 replicates. Data was collected on oviposition holes on leaves of common bean by BSM, BSM population dynamics, leaf damage score by BFB, and population dynamics of BFB. The number of oviposition holes, the mean cumulative number of BSM, the mean leaf damage scores and the mean cumulative number of BFB were significantly higher (P < .05) in dense plots (15cm x 15cm) than in the other plots. The activity of BSM and BFM increased over time. The Principal Component Analysis revealed that the first two components accounted for 99.17% of the variation. Linear discriminant analysis with Mahalanobus distances with an 87.5% cross-validation by Jacknife procedure revealed that spatial orientation of 20cm x 20cm and 30cm x 30cm were very similar and significantly (F = 99.27, df = 3, 12, P < .001) different from the others. For pest management purposes, plant orientations of 20cm x 20cm and 30cm x 30cm can be recommended since they recorded low BSM and BFB activity. For future perspective, it is important assess the effect of different plant orientation on yield and pest parameters concurrently.

Orientation-Dependent Soft Plasmonics of Gold Nanobipyramid Plasmene Nanosheets.

In parallel to the burgeoning field of soft electronics, soft plasmonics focuses on the design and fabrication of plasmonic structures supported on elastomers and to understand how their properties respond to mechanical deformations. Here, we report on a partial ligand-stripping strategy to fabricate elastomer-supported gold nanobipyramid (NBP) plasmene nanosheets. Unlike spherelike building blocks, NBP-building blocks display complex orientation-dependent plasmonic responses to external strains. By collecting polarized plasmonic resonance spectra in conjunction with electrostatic eigenmode modeling, we reveal simultaneous changes in interparticle spacing and spatial orientations of NBP building blocks under mechanical strains. Such changes are directly related to initial NBP packing orders. Further analysis of strain sensitivities for various NBP plasmenes indicated that plasmonic spectra of ∼45° oriented samples are mostly susceptible to strain at acute polarized angles. The results presented may enable novel applications in future soft optoelectronic devices in sensing, encryption, and data storage.

Spirocyclic Nitroxide Biradicals: Synthesis and Evaluation as Dynamic Nuclear Polarizing Agents

AbstractA method for the synthesis of rigid nitroxide biradicals with various spatial orientations between the radical centers is reported. Diketones were employed as substrates for tin amine protocol (SnAP) reagents to provide the parent spirocyclic diamines. Oxidation by peroxyacids provided the corresponding nitroxide biradicals. A set of four different biradicals with various interelectron distances and torsion angles between the radical planes was synthesized using this method. The exact geometries were determined by X‐ray crystallography and the biradicals were investigated by EPR spectroscopy and evaluated for their dynamic nuclear polarization (DNP) performance. 1H‐DNP enhancements in the range of 1.2–2.1 at 14.1 Tesla (600 MHz spectrometer) were achieved. This synthetic methodology opens a promising alternative to access nitroxide biradicals with various torsional angles and inter radical distances.

Variability of monsoon inversion over the Arabian Sea and its impact on rainfall

AbstractThis work investigates the spatial and temporal variability of the monsoon inversion (MI) over the Arabian Sea for the study of 37‐years period (1980–2016) using MERRA version2 (MERRA2) reanalysis and downscaled simulations generated with the Weather and Research Forecasting (WRF) model. After validating the downscaled products with the observations from four radiosonde stations (Salalah, Mumbai, Goa and Mangalore), we analysed the variability of MI from diurnal to seasonal scales. The diurnal evolution of the MI suggests that radiative cooling over the Arabian Peninsula at night, together with the onset of boundary layer jets along the coast of Oman, play an important role in amplifying the intensity and spatial extent of the MI during night and into the early morning hours. A seasonal analysis of the simulated winds and MI reveals that WRF reproduced the monsoon characteristics as observed in MERRA2 reanalysis, including the spatial and vertical orientations of the MI. The downscaled winds are slightly overestimated (by 1–2 m⋅s−1) over the Arabian Sea, which resulted in an increased simulated wind shear over the western Arabian Sea, ultimately manifested in the form of an enhanced MI. We further investigated the variability of the lower tropospheric wind speed and associated changes in MI over the 37‐year period. This reveals a significant decreasing trend during the summer monsoon over the western Arabian Sea. We argue that this led to a decreasing trend in the lower tropospheric wind shear and advection of temperature and hence, reduced the frequency of occurrence of the MI (shown in graphical abstract).

Ambipolar Trap for Dust Particles in a V-Shaped Homogeneous Positive Column of Glow Discharge at Low and Medium Pressures

The spatial distribution of dust particles in a low-pressure homogeneous positive column of a dc glow discharge in a right-angle curved (V-shaped) glass tube in different spatial orientations was observed and analyzed. It is found that in all cases, the ambipolar field prevents charged dust particles from falling on the wall of the glass tube. As a result, the design of the curved glass tube makes it possible to create in practice a simple and effective ambipolar trap and to implement the collection and control of dust particles in plasma.