Stationary Core Research Articles

Inductive sensor for measuring linear displacement and velocity – Version with stationary magnetic core

The article describes a displacement sensor designed and manufactured in the Rock Deformation Laboratory of the Strata Mechanics Institute of the Polish Academy of Sciences for cooperation with the GTA-10 triaxial cell. This sensor measures the displacement and velocity of the strength machine's piston.The sensor has the form of a single-layer induction coil made of spring steel with a fixed magnetic core cooperating with the LC oscillator. The coil elongates during measurement without friction, causing oscillation frequency changes, unlike the LVDT sensor, where core movements produce a voltage signal. In this way, a displacement-frequency transducer is realised.The presence of the core linearizes the transducer's displacement-frequency characteristic and increases its sensitivity in this case. Moreover, the core increases the inductance of the sensor, which allows the increase in the capacitance of the resonant circuit and thus, the stability of the oscillations, which are influenced by the parasitic capacitances of the connections. In this way, a resolution of the transducer of less than 500 nm was achieved, with a measuring range of 70 mm (relative resolution 105). The new inductive sensor replaced the resistance displacement sensor, which had been used previously.The article shows the mathematical background of the sensor functioning as a displacement-frequency transducer, its structure and examples of its application.

Optical Magnus radiation force and torque on a dielectric layered cylinder with a spinning absorptive dielectric core.

A dielectric cylindrical shell material with an inner stationary absorptive core (or, equivalently, a concentric layered cylinder) illuminated by an axisymmetric wave field (in 2D) with arbitrary polarization will experience a time-averaged radiation force along the direction of wave propagation, whereas the transverse component vanishes as required by symmetry. Counterintuitively, the present analysis shows that when the inner absorptive core material rotates with an initial angular velocity Ω0 around its main geometrical axis, a transverse radiation force component arises (in addition to a longitudinal force) as well as an axial radiation torque component in plane waves. This phenomenon is the analog of the classical hydrodynamic Magnus effect. In this analysis, the instantaneous rest-frame theory and the modal series expansion method in cylindrical coordinates are utilized to formulate the EM/optical scattering from a cylindrical shell with arbitrary thickness, and to compute the optical radiation force and torque vector components. Particular emphases are given on the size parameter of the cylindrical shell, the layer thickness, the angular rotation of the inner absorptive core, and the polarization (TM or TE) of the incident plane waves. Numerical computations illustrate the analysis and explicate the behaviors of the longitudinal, transverse, and axial radiation force and torque components. Related applications for the optical Magnus effect in radiation force and torque investigations can benefit from the results of the present analysis in spin-optics, rotational Doppler shift for optical waves, optical tweezers, optical manipulation of elongated spinning objects, and particle rotation.

Use of 2-D and 3-D unsteady RANS in the computation of wall bounded buoyant flows

The present study numerically investigates the performance of a range of RANS turbulence closures with different near-wall treatments in the prediction of natural convection flows. Comparisons are performed of both 2-D and 3-D steady and time-dependent computations in differentially heated cavities, which involve very simple geometries, but give rise to complex flow physics of relevance to cooling applications, including safety features of nuclear reactors. The turbulence closures assessed include eddy-viscosity and second-moment closures and involve low-Reynolds-number versions (LRN) which fully resolve the viscous sublayer, as well as high-Reynolds-number versions (HRN) which adopt wall function treatments to prescribe boundary conditions for the wall shear stress and heat flux.In the 2-D computations of the tall rectangular cavity, there are only small deviations in the predictions of different models, and these are mainly confined to the local Nusselt number comparisons. Among the LRN models, the second-moment EBRSM is in good agreement with the data, while the LRN eddy-viscosity models under-estimate the Nusselt number levels. The HRN models, when used with the standard log-law-based wall function, over-estimate the Nusselt number. During the course of the present investigation, a new, more general, version of the Analytical Wall Function (AWF) has been developed and introduced to the open-source CFD code utilised. Here, this more general numerical wall treatment brings the HRN k-ε predictions of the Nusselt number to very close agreement with the experimental data.In the 2-D square cavity computations, the simulations focus on a high Rayleigh number (Ra) of 1011, for which DNS data has recently become available. At such high Ra value all the models are challenged due to the unsteadiness of the flow and the presence of a largely stationary and laminar core, and thin turbulent boundary layers. Assessment of different 3-D configurations of the same square cavity demonstrates that the effect of the turbulent mixing in the third (z) direction is significant, but can be taken into account by introducing a cavity depth of D=0.15H, matching that used in the DNS study. The deviations in the predictions of the different models are stronger than those observed in the corresponding rectangular cavity comparisons, especially for the local Nusselt number distribution. As is also the case in the rectangular cavity, the eddy-viscosity models under-estimate the Nusselt number, while the EBRSM with the more elaborate turbulent heat flux model once more is closest to the DNS data. All HRN models with the log-law wall function severely under-estimate the Nusselt number levels. Introduction of the buoyancy-adapted AWF leads to substantial predictive improvements. The HRN AWF approach is thus shown to be a reliable and cost-effective modelling strategy for natural convection flows.

Development of a novel MR clutch featuring tooth-shaped disc

In this research, we focus on development of a new configuration of magneto-rheological fluid (MRF) based clutch (MRC) featuring a tooth-shaped disc with multiple teeth acting as multiple magnetic poles of the clutch. The tooth-shaped disc is placed in a clutch housing composed of the left housing and the right housing. The inner face the housing also has tooth shaped features mating with the teeth of the disc through the working MRF. Excitation coils are placed directly on stationary winding cores placed on both side of the clutch housing. An air gap of 0.3 mm is left between the housing and the winding cores to ensure the housing can freely rotate against the winding cores. After the introductory part, configuration of the MRC is introduced and the transmitted torque of the MRC is derived. An optimization process to minimize the overall volume of the proposed clutch, which can generate a required maximum braking torque, is then conducted. The optimal results show that the overall volume of the proposed MRC is significantly reduced compared to a referenced conventional MRC (0.159 m3 vs. 0.295 m3). A prototype of the proposed MRC is fabricated for experimental works and good agreement between the experimental results and simulated ones is archived.

Phytoplankton Increase Along the Kuroshio Due to the Large Meander

The Kuroshio Large Meander (LM) is known to be highly aperiodic and can last from 1 to 10 years. Since a stationary cold core formed between the Kuroshio and the southern coast of Japan off Enshu-Nada and approaching warm saltier water on the eastern side of the LM changes the local environment drastically, many commercially valuable fish species distribute differently from the non-LM period, impacting local fisheries. Despite this importance of the LM, the influences of the LM on the low trophic levels such as phytoplankton and zooplankton have still been unclear. In this study, satellite daily sea surface chlorophyll data are analyzed in relation to the LM. The results show positive anomalies of the chlorophyll-a concentration along the Kuroshio path during the LM periods, 2004–2005 and 2017–2019, from the upstream off Shikoku to the downstream (140°E). These positive anomalies are started by the triggering meander generated off south of Kyushu, which then slowly propagates to the downstream LM region in both the LM periods. Even though the detailed patterns along the Kuroshio region in the two LM periods were different, similar formations of the positive anomalies on the western side of the LM with shallower mixed layer depth are observed. Furthermore, we found clear relationships between the minimum distance from several stations along the coast to the Kuroshio axis and the mean chlorophyll-a anomaly, with significant correlations with the distance from different stations.

Analysis of JET component parameters of AGN - brightness, speed, size, distance and acceleration

We statistically analysed the jet component parameters of superluminal sources which comprises of radio galaxy (G), radio quasar (Q) and BL Lac (B) objects. Subsamples were formed based on brightness, speed, size, distance D from the assumed stationary core, jet components with positive and negative perpendicular and parallel acceleration. Results show that there is a strong positive correlation between the jet component size and distance away from the core, which supports the self-similarity model of AGN evolution and that jet component accelerations are independent of any size, distance from the core, radio power and speed of the jet component. Moreover, jet components with negative/positive acceleration have similar range in values in the observed parameters.

A microbenchmark characterization of the Emu chick

The Emu Chick is a prototype system designed around the concept of migratory memory-side processing. Rather than transferring large amounts of data across power-hungry, high-latency interconnects, the Emu Chick moves lightweight thread contexts to near-memory cores before the beginning of each memory read. The current prototype hardware uses FPGAs to implement cache-less “Gossamer” cores for computational work and rely on a typical stationary core (PowerPC) to run basic operating system functions and migrate threads between nodes. In this multi-node characterization of the Emu Chick, we extend an earlier single-node investigation [1] of the memory bandwidth characteristics of the system through benchmarks like STREAM, pointer chasing, and sparse matrix-vector multiplication. We compare the Emu Chick hardware to architectural simulation and an Intel Xeon-based platform. Our results demonstrate that for many basic operations the Emu Chick can use available memory bandwidth more efficiently than a more traditional, cache-based architecture although bandwidth usage suffers for computationally intensive workloads like SpMV. Moreover, the Emu Chick provides stable, predictable performance with up to 65% of the peak bandwidth utilization on a random-access pointer chasing benchmark with weak locality.

Mass reduction of superconducting power generators for large wind turbines

High temperature superconductors (HTS) enable very compact electric machines with high power density. Here, an HTS power generator based on authors’ previous double claw pole design is studied and improved. The original design of the double claw pole machine features a stationary field core to provide support and access to the superconducting field winding and its cryostat. It does not serve any other purpose. However, a homopolar field passes through it. The improvement was made to replace the field core by iron-cored copper coils, creating an inner stator within the generator to increase the electric loading. Through this step, the power output of the generator was increased from 10 to 11.6 MW, increasing the power density from 54.28 to 63.54 W/kg while maintaining the same outer diameter.

Kinematics of the parsec-scale jet of the blazar AO 0235+164

AbstractRadio interferometric maps of the blazar AO 0235+164 show the existence of a stationary core, and a compact jet composed of multiple receding components. In this work, we determined the structural characteristics of these jet components (core-component distance, position angle, flux density, etc.) using the statistical method for global optimization Cross-Entropy (CE). The images we analyzed were extracted from public databases, totaling 41 images at 15 GHz and 128 images at 43 GHz. Using criteria such as the value of the CE merit function, and mean residuals, we determined the optimum number of components in each map analyzed in this work. We found that jet components are distributed across all four quadrants on the plane of the sky, indicating a possible non-fixed jet orientation during the monitoring interval. The time evolution of the equatorial coordinates of the jet components were used to determine their respective speeds, ejection epochs, and mean position angles on the plane of the sky. We have identified more than 20 components in the jet of AO 0235+164, with their apparent speeds ranging roughly from 2c to 40c, and distributed across all four quadrants on the plane of the sky. From the kinematics of these jet components we could derive a lower limit of about 39 for its bulk jet Lorentz factor and an upper limit of approximately 42 degrees for its jet viewing angle.

Abstract 1886: mGluR1 drives invasion of proneural subtype of glioblastoma cells

Abstract A major cause for the therapeutic failure and subsequent morbidity and mortality of glioblastoma (GBM) is the aggressive invasion of malignant cells into the surrounding normal brain that effectively renders complete surgical resection impossible and virtually assures recurrent tumor growth. Multi-omic profiling of GBM led to their molecular sub-classification into two distinct molecular subtypes: proneural (PN) and mesenchymal (MES). However, very little is known about shared or distinct invasion processes of cells in these genomically different subtypes. Using Microarray gene expression profiles of microdissected paired stationary core and invasive rim samples from 19 patients, we demonstrated that invasive gene signature of MES subtypes differs from PN. Specifically, using three orthogonal but intersecting bioinformatic approaches, i.e. gene set variation analysis, causal network analysis, and iRegulon analysis; we discovered that genes differentially expressed between PN core and rim could, to a meaningful degree, be accounted for based on their annotation as “regulated by the transcription factor REST”. REST functions as a repressor of gene expression. Of the genes repressed by REST, mGluR1 (Metabotropic Glutamate Receptor 1) was significantly overexpressed at the rim of PN glioma cells as compared to the core. Finally, we also investigated the role of mGluR1 in glutamate induced glioma cell migration; our results show that glutamate stimulates migration of proneural-like glioma cells (A172) as compare to non-proneural-like glioma cell (T98G). mGluR1 activation by glutamate has shown to induce activation of Pyk2 and Src in astrocytes; knockout of mGluR1 is not embryonic lethal. In summary, our data demonstrate that glutamate-induced glioma cell migration of PN subtype of GBM is dependent on mGluR1 and thus raises the prospect that therapeutic targeting of mGluR1 may be a novel approach to controlling the invasion of this deadly disease. Citation Format: Alena Gladwin, Sen Peng, Jeff Kiefer, Seugchan Kim, Michael Berens, Harshil D. Dhruv. mGluR1 drives invasion of proneural subtype of glioblastoma cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1886. doi:10.1158/1538-7445.AM2017-1886

On the Lorentz factor of superluminal sources

We investigate the properties of features seen within superluminal sources often referred to as components. Our result indicates a fairly strong correlation of r ∼ 0.5 for quasars, r ∼ 0.4 for galaxies and r ∼ 0.7 for BL Lac objects in our sample between component sizes and distances from the stationary core. The assumption of free adiabatic expanding plasma enables us to constrain the Lorentz factor for superluminal sources. Our estimated Lorentz factor of γ ∼ 9–13 for quasars, γ ∼ 7–11 for galaxies and γ ∼ 4–9 for BL Lac objects indicates that BL Lacs have the lowest range of Lorentz factors.

Abstract PR12: Identifying different functional mechanisms of invasion from mesenchymal and proneural subtypes of glioblastoma

Abstract Glioblastoma multiforme (GBM) is the most frequent, aggressive and invasive type of primary brain tumors. Clinical management of patients with GBMs is confounded by the tumor cells' tendency to migrate and invade into adjacent brain. Understanding and targeting these invasive/dispersive malignant cells would address an unmet clinical need, and have a significant impact on patient quality of life and survival. The purpose of this study is to identify expression changes associated with distinct GBM subtypes that differentiate stationary core and invasive rim tumor cells. We used GBM invasion gene expression data (GSE12689), which consists of microdissected paired core v rim sets from 19 patient samples (Hoelzinger DB, et al Neoplasia. 2005. PMID: 1490313). Gene expression data on the 19 core samples were analyzed to determine specific GBM subtypes using the mesenchymal (MES) and proneural (PN) gene expression signatures (Verhaak RG et al Cancer Cell. 2010. PMID: 2818769.) resulting in 6 instances of MES, 7 PN, 3 uncertain-MES and 3 other. After subtype analysis, differentially expressed genes (DEGs) were identified between core and rim for the Mes and PN groups. Using a p-value threshold 0.005 (or p < 0.01), 216 (468) DEGs (core vs. rim) were identified from the MES-subtype, and 497 (1,028) DEGs were identified from the PN-subtype. The larger number of DEGs in the PN subtype suggests a more substantial (greater) adaptation of transcriptional change is necessary to transition to a invasive phenotype. The smaller number of changes in the MES samples suggests that cells of this form of GBM have an inherent migratory phenotype. Curiously, there was little gene overlap between MES and PN DEGs. A knowledge mining analysis was done to characterize biological concepts represented by the DEGs in each molecular subtype. The PN rim signature was enriched for genes involved in neuronal processes associated with synapse development and function. The PN core signature displayed genes associated with cell cycle progression. The MES core and rim signature represented a less homogeneous functional grouping of genes. There was a grouping of genes associated with vesicle movement, such as ARF1 and ARF3, associated with the MES rim. One gene of importance noted in the MES rim was autotaxin, which we have previously shown to be important in GBM invasion (Hoelzinger DB, et al. J Neurooncol. 2008 PMID: 17928955). No significant enriched biological concepts were evident in the MES core, however, individual genes of interest in the core such as the insulin receptor, BDNF and sonic hedgehog (SHH) were observed. Lastly, the ligand DLL4 and notch receptor (NOTCH1) are present, suggesting Notch signaling in the MES core. In summary, we analyzed a unique clinical GBM gene expression resource to identify patterns of differentially expressed genes associated with the invasive rim of MES and PN GBM samples. Molecular subtyping of the tumor has a marked influence on the changes in gene expression coincident to invasion. Disparity in the changes in patterns of differential gene expression between MES and PN GBM argues for wide-ranging adaptations necessary to affect dispersion in the brain, including tumor:microenvironment interactions, tumor cell adoption of a invasive phenoptype, and likely proliferative-, survival- and developmental-related changes. Such wide-ranging accommodation to succeed in invasion based on molecular subtyping raises opportunities by which to assess what the points of vulnerability may be in these malignant cells while they navigate through the brain to set up distant sites of tumor growth. (Supported by NIH CA U01CA168397) This abstract is also presented as Poster B92. Citation Format: Sungwon Jung, Seungchan Kim, Jeff Kiefer, Michael E. Berens. Identifying different functional mechanisms of invasion from mesenchymal and proneural subtypes of glioblastoma. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr PR12.

A Three-decade X-band VLBI Study of 3CR Lobe-dominated Quasar Nuclei

We report X-band VLBI observations of several 3CR lobe-dominated quasar nuclei from 1981 to 2010, mostly obtained with the NRAO VLBA. The goal is to follow flux density outbursts and to fully determine the jet morphology and kinematics on 1-100 pc scales. In 3C207, the core region has flux outbursts at mean intervals of ~7 yr; one of these is actually a double outburst from a stationary true core and a swinging component ~0.5 mas apart. The position angle (PA ) of the swinging component varies by ~40°, while the PA values of the jet components span ~25°. The jet extends to ~25 mas. Average superluminal speeds are ~10c . One component shows apparent acceleration from 7c to 14c at 2-3 mas from the true core, in a jet recollimation zone that redirects the flow toward PA ~90°. Individual jet components expand until reaching the recollimation zone. In 3C263 and other objects, some of the same phenomena are seen, including ejection of jet components over a range in PA , superluminal motion, and apparent acceleration, but to a lesser degree. Possible physical interpretations involving beaming, orientation, projection, precession, and magnetic effects are discussed.

R-Process nucleosynthesis in high entropy environment in explosion of supernova type II and neutron star formation

AbstractIt is generally acknowledged that Type II supernovae result from the collapse of iron core of a massive star which, at least in some cases, produces a neutron star. At this stage, the neutrinos are produced by neutronization which speeds up as collapse continues. During collapse an outward bound shock wave forms in the matter falling onto the nearly stationary core. The conditions behind the shock at 100 to 200 km are suitable for neutrino heating. This neutrino heating blows a hot bubble above the protoneutron star and is the most important source of energy for Supernova explosion. At this stage, we try to attain the r-process (rapid neutron capture process) path responsible for the production of heavy elements beyond iron, which are otherwise not possible to be formed by fusion reactions. The most interesting evolution occurs as temperature falls from 1010 K to 109 K. At these high temperature conditions, the critical fluids after fusion reactions are forbidden and transform into the respective atoms by r-process path which on beta decaying produce the ultimate elements of the periodic chart.Another astrophysical parameter needed for our analysis is neutron number density which we take to be greater than 1020 cm−3. With these, at different entropy environments, we assign the neutron binding energy that represents the r-process path in the chart of nuclides. Along the path, the experimental data of observed elements matches our calculated one. We find that an entropy of ~300 with Ye ≃ 0.45 can lead to a successful r-process. It produced heavy neutron-rich nuclei with A ≃ 80 – 240. Later ejecta are neutron-rich (Ye ≤ 0.5) and leaves behind a compact neutron star.

Transient relativistic ejections and stationary core in XTE J1752−223

ABSTRACT The Galactic X-ray transient XTE J1752−223 was shown to have properties of black hole binary candidates. As reported in our previous paper, we identified transient and decelerating ejecta in multi-epoch Very Long Baseline Interferometry (VLBI) observations with the European VLBI Network (EVN) and the NRAO Very Long Baseline Array (VLBA). Here we present new EVN and VLBA data in which a new transient ejection event and later a stationary component are identified. The latter is interpreted as a reappearance of the radio core/compact jet during the transition from soft to hard X-ray state. This component appears to be highly variable in brightness although effects of tropospheric instabilities might play a role too. We also re-analyse the earlier VLBI data and find that the transient ejecta closer to the core position has significantly higher proper motion, further strengthening the case for strongly decelerating ejecta on the scale of several hundred milliarcsecond, never observed in X-ray binaries before. Although the distance of the source is not well constrained, it is clear that these ejectas are at least mildly relativistic at the early stages. Moreover, we show the large scale environment of the transient from the Westerbork synthesis array data recorded in parallel during the EVN run.

Analysis of magnetic force production in slider actuators combining analytical and finite element methods

The production of magnetic forces in a magnetic actuator is the focus of the present analysis. Magnetic circuit analysis is used to investigate the direction as well as the expected order of magnitude of the force that attracts the armature into the central portion of a stationary core. A sequence of finite-element based solutions is used to investigate magnetic saturation and to determine the force-displacement characteristic. The analytical approach is based on the principle of virtual work and Ampere's law. The force calculations based on numerical field solutions employ the methods of weighted Maxwell stress tensor and the classical virtual work. The more accurate field-derived solutions are used to explain the limitations of the analytical calculations. At the end, an alternative approach to compute the force numerically is proposed. This method is based on the principle of virtual work, but only one field solution is required.

Precision pneumatic pressure measurement with diaphragm-based mechatronic devices

A clamped circular metallic diaphragm, with shallow spherical shell deformation, elongates spherically proportional to the pressure acting on it. By making use of the inflation characteristics and mechanical properties of the diaphragm, three types of pneumatic pressure sensor are proposed in this article. In the first type, an optical mirror is engraved on its outer surface in an optimal position falling midway between its vertex and circumference. A laser beam is made to incident on the mirror and it gets deflected to fall over a matrix of photocells; the excitation of a particular cell in the coordinates of the matrix determines the pressure acting on the diaphragm. In the second proposal, a weightless secondary coil of a transformer is fixed around the vertex of the diaphragm which would move around a stationary magnetic core. The excitation of the primary coil wound over the magnetic core causes a voltage to be picked up in the secondary coil which would depend upon the displacement of the vertex because of pressure. The third type of the transducer is a capacitance pickup arrangement wherein the pressure is converted into capacitance and it is sensed and displayed as pressure. Furthermore, as an extension of the work, the motion of the diaphragm is mechanically coupled to a stylus for producing hard copy of the pressure over a strip chart.

A concentric three element radial scanning optical coherence tomography endoscope

We have developed a 2.1 mm outer diameter optical coherence tomography endoscope that provides radial scans of luminal structures. The endoscope consists of three elements: (1) a stationary central core containing the fibers and focusing elements, (2) a rotating intermediate tube with a distal rod prism, and (3) a stationary sterilized glass cover. This design enables radial and spiral scanning and allows adjustment of the axial focal distance. Additionally, this design is capable of focusing light from multiple fibers into tissue. The performance of the endoscope was demonstrated in a study of tissue engineered blood vessels imaged at various time points during development.

Paper: Evaluations of toner supply capabilities for some typical two-component developing systems

Two-component developing system has an advantage in durability for high speed and heavy-duty use in an electrophotographic laser printer. For achieving high speed and heavy duty printing, the most important factor is toner supply capability from developing rolls to a photo-conductor surface.In this study, the capability with print speed for each method on the two-component developing system employing magnet rolls composed of rotating sleeves with stationary core including a donor rolls system is examined. For the examinations, some assumptions for factors, which affects to the toner supply capability, and toner mass on the photo-conductor are made.As a result, we found typical speed ranges and their characteristics for the toner supply capability in the two-component developing systems. 700 mm/s print speed can be achieved by the examined methods. The print speed exceeding 1500 mm/s can be achieved by a method of two-roll use of the rotating sleeve with stationary core magnet rolls of 50 mm diameters with different rotation direction.

Effect of Volumetric Organic Loading on the Nitrogen Removal Rate by Immobilised Activated Sludge

Activated sludge was immobilised in a porous ceramic carrier to create a stationary core of a bio-reactor. Municipal wastewater was treated in this reactor under varied conditions of volumetric organic loading rate (expressed by chemical oxygen demand (COD)) that were the following: 6.5, 8.0, 20.8, 48.8 g COD l&minus1 d−1. The rate constants of ammonification, nitrification and denitrification under aerobic conditions were determined. All rate constants increased with a growth in volumetric loading rate, but the highest loading value of 48.8 g COD l&minus1 d−1 limited the ammonification and nitrification rates.