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Lee, Jae Hwa, Hyung Jin Sung, and Ronald J. Adrian. "Space–time formation of very-large-scale motions in turbulent pipe flow." Journal of Fluid Mechanics 881 (October 25, 2019): 1010–47. http://dx.doi.org/10.1017/jfm.2019.786.
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We examine the origin of very-large-scale motions (VLSMs) in fully developed turbulent pipe flow at friction Reynolds number, $\mathit{Re}_{\unicode[STIX]{x1D70F}}=934$, using data from a direct numerical simulation. The VLSMs and the packet-like large-scale motions (LSMs) found in this study are very similar to those found in earlier studies. Three-dimensional time-evolving instantaneous fields show that one component of the process leading to the large streamwise length of VLSMs is the concatenation of adjacent streamwise LSMs caused by the continuous elongation of LSMs due to the strain component of the mean shear. Spatial organization patterns of the VLSMs and LSMs and their properties are studied by separating auto-correlation of the streamwise velocity fluctuations into the components of the VLSM and the LSM defined by low-pass/high-pass filtering in the streamwise direction. The structures of the two-point spatial correlations of the streamwise velocity component of the VLSMs and the LSMs in the streamwise-azimuthal plane are characterized by multiple maxima and complex patterns that beg explanation in terms of patterned coherent arrangements of the LSMs. Using proper orthogonal decomposition (POD), it is found that the X-shape correlation pattern of the VLSMs results from the superposition of very long helically inclined structures and streamwise-aligned structures. Further explanation of the patterns in the correlations of the VLSMs and LSMs is provided through the study of synthetically constructed arrangements of simple hairpin packet models of the LSM. Head-to-tail alignment of the model packets along streamwise and helical directions suggested by the eigenvalues of the POD creates a pair of long roll-cells centred above the logarithmic layer, and bracketing the LSMs. These roll-cells are pure kinematic consequences of the induction within the LSM packets, but they may also serve to organize smaller packets.
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Kassoy, D. R. "The Zeldovich spontaneous reaction wave propagation concept in the fast/modest heating limits." Journal of Fluid Mechanics 791 (February 22, 2016): 439–63. http://dx.doi.org/10.1017/jfm.2015.756.
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Quantitative mathematical models describe planar, spontaneous, reaction wave propagation (Zeldovich, Combust. Flame, vol. 39, 1980, pp. 211–214) in a finite hot spot volume of reactive gas. The results describe the complete thermomechanical response of the gas to a one-step, high-activation-energy exothermic reaction initiated by a tiny initial temperature non-uniformity in a gas at rest with uniform pressure. Initially, the complete conservation equations, including all transport terms, are non-dimensionalized to identify parameters that quantify the impact of viscosity, conduction and diffusion. The results demonstrate unequivocally that transport terms are tiny relative to all other terms in the equations, given the relevant time and length scales. The asymptotic analyses, based on the reactive Euler equations, describe both induction and post-induction period models for a fast heat release rate (induction time scale short compared to the acoustic time of the spot), as well as a modest heat release rate (induction time scale equivalent to the acoustic time). Analytical results are obtained for the fast heating rate problem and emphasize the physics of near constant-volume heating during the induction period. Weak hot spot expansion is the source of fluid expelled from the original finite volume and is a ‘piston-effect’ source of acoustic mechanical disturbances beyond the spot. The post-induction period is characterized by the explosive appearance of an ephemeral, spatially uniform high-temperature, high-pressure spot embedded in a cold, low-pressure environment. In analogy with a shock tube the subsequent expansion process occurs on the acoustic time scale of the spot and will be the source of shocks propagating beyond the spot. The modest heating rate induction period is characterized by weakly compressible phenomena that can be described by a novel system of linear wave equations for the temperature, pressure and induced velocity perturbations driven by nonlinear chemical heating, which provides physical insights difficult to obtain from the more familiar ‘Clarke equation’. When the heating rate is modest, reaction terms in the post-induction period Euler equations exhibit a form of singular behaviour in the high-activation-energy limit, implying the need to use a nonlinear exponential scaling for time and space, developed originally to describe spatially uniform thermal explosions (Kassoy, Q. J. Mech. Appl. Maths, vol. 30, 1977, pp. 71–89). Here again the result will be the explosive appearance of an ephemeral spatially uniform high-temperature, high-pressure hot spot. These results demonstrate that an initially weak temperature non-uniformity in a finite hot spot can be the source of acoustic and shock wave mechanical disturbances in the gas beyond the spot that may be related to rocket engine instability and engine knock.
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WEBB, G. M., G. P. ZANK, R. H. BURROWS, and R. E. RATKIEWICZ. "Alfvén simple waves." Journal of Plasma Physics 77, no. 1 (2010): 51–93. http://dx.doi.org/10.1017/s0022377809990596.
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AbstractMulti-dimensional Alfvén simple waves in magnetohydrodynamics (MHD) are investigated using Boillat's formalism. For simple wave solutions, all physical variables (the gas density, pressure, fluid velocity, entropy, and magnetic field induction in the MHD case) depend on a single phase function ϕ, which is a function of the space and time variables. The simple wave ansatz requires that the wave normal and the normal speed of the wave front depend only on the phase function ϕ. This leads to an implicit equation for the phase function and a generalization of the concept of a plane wave. We obtain examples of Alfvén simple waves, based on the right eigenvector solutions for the Alfvén mode. The Alfvén mode solutions have six integrals, namely that the entropy, density, magnetic pressure, and the group velocity (the sum of the Alfvén and fluid velocity) are constant throughout the wave. The eigenequations require that the rate of change of the magnetic induction B with ϕ throughout the wave is perpendicular to both the wave normal n and B. Methods to construct simple wave solutions based on specifying either a solution ansatz for n(ϕ) or B(ϕ) are developed.
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Koniak, Marcin, Piotr Jaskowski, Radovan Madleňák, and Jurijus Zaranka. "Analysis of real-time energy transfer possibilities at intersections with consideration of energy storage." Archives of Transport 73, no. 1 (2025): 195–206. https://doi.org/10.61089/aot2025.5dtybt57.
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Issues related to braking and acceleration in vehicles represent both technical and environmental challenges, regardless of the type of drive, whether combustion or electric. In conventional vehicles, the emission of particulate matter is a problem associated with the friction between brake pads and discs, leading to air pollution and health hazards. Brake dust contributes to up to 55% of particulate matter in urban environments. In electric vehicles, the processes of braking and rapid acceleration affect battery wear; however, thanks to energy recovery technology, it is possible to recuperate up to 70% of the kinetic energy. This paper proposes a solution involving the placement of induction loops before intersections with traffic lights to enable the recovery and storage of energy, which could be used to power vehicles waiting at intersections, as well as placement behind intersections to supply power to vehicles accelerating when leaving the intersection. The study considers the application of various energy storage technologies, such as flow batteries, supercapacitors, and flywheels. Each of these technologies offers unique benefits and limitations, such as long operational life, a high number of charge/discharge cycles, and environmental friendliness. Simulations performed using AIMSUN.Next software made it possible to analyze energy consumption and pollutant emissions in various scenarios, indicating the potential benefits of traffic optimization, the use of electric vehicles, and energy recovery. The research results highlight the importance of traffic smoothness and the use of energy storage technologies to reduce pollutant emissions (possible reduction: CO2 by over 40%, NOx by 48%, PM by 73%, and VOC by 40%) and energy consumption (lack of smooth traffic flow leads to approximately 159% higher energy use). The proposed use of energy storage technologies at intersections may significantly decrease particulate and carbon dioxide emissions. The final choice of energy storage technology will depend on local conditions, such as space availability, investment costs, and market availability.
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Gaitán, María I., Pietro Maggi, Jillian Wohler, et al. "Perivenular brain lesions in a primate multiple sclerosis model at 7-tesla magnetic resonance imaging." Multiple Sclerosis Journal 20, no. 1 (2013): 64–71. http://dx.doi.org/10.1177/1352458513492244.
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Background Magnetic resonance imaging (MRI) can provide in vivo assessment of tissue damage, allowing evaluation of multiple sclerosis (MS) lesion evolution over time – a perspective not obtainable with postmortem histopathology. Relapsing–remitting experimental autoimmune encephalomyelitis (EAE) is an experimental model of MS that can be induced in the common marmoset, a small new world primate, and that causes perivenular white matter (WM) lesions similar to those observed in MS. Methods Brain lesion development and evolution were studied in vivo and postmortem in four marmosets with EAE through serial T2- and T2*-weighted scans at 7-tesla. Supratentorial WM lesions were identified and characterized. Results Of 97 lesions observed, 86 (88%) were clearly perivenular, and 62 (72%) developed around veins that were visible even prior to EAE induction. The perivenular configuration was confirmed by postmortem histopathology. Most affected veins, and their related perivascular Virchow-Robin spaces, passed into the subarachnoid space rather than the ventricles. Conclusion As in human MS, the intimate association between small veins and EAE lesions in the marmoset can be studied with serial in vivo MRI. This further strengthens the usefulness of this model for understanding the process of perivenular lesion development and accompanying tissue destruction in MS.
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Kant, R., and K. L. Deckert. "Laser-Induced Heating of a Multilayered Medium Resting on a Half-Space: Part II—Moving Source." Journal of Heat Transfer 113, no. 1 (1991): 12–20. http://dx.doi.org/10.1115/1.2910516.
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Direct access storage devices (DASDs) are widely used in the computer industry to store and manage data. In conventional magnetic recording, an induction head flying very close to the disk surface alters the polarization of the magnetic field of the disk surface to erase and/or write the information on the disk. However, a new technology known as magneto-optical recording or optical recording has considerable promise to increase data densities and reliability of data storage. In magneto-optical storage, magnetic fields are altered by a laser source, which heats the magnetic medium beyond its Curie point, a temperature at which the magnetic medium loses its magnetization. This domain with zero magnetization is subsequently reversed by using an induction magnet. All these processes take place when the disk is rotating at a very high speed with respect to the laser source. An optical disk is a multilayered medium consisting of a thick glass disk on which many layers of different materials are sputtered, only one layer of which serves as a magnetic medium. Therefore, in this paper, a problem of laser-induced heating of a multilayered medium resting on a half-space is considered when the laser is translating with respect to it. The transient heat conduction equation is solved by employing the Laplace transform in the time domain and the Fourier Transform in the x, y dimensions. The resulting ordinary differential equation is solved and the inversion of the Laplace transform is obtained by a technique developed by Crump. The Fourier inversion is obtained by using a Fast Fourier Transform. The technique developed here is then applied to calculate domain size for recorded bits for a given disk, laser power, source characteristics, and rotational velocity.
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Welch, Dale R., and Thomas P. Hughes. "Effect of target-emitted ions on the focal spot of an intense electron beam." Laser and Particle Beams 16, no. 2 (1998): 285–94. http://dx.doi.org/10.1017/s0263034600011617.
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Intense electron beams are known to produce surface plasmas when they strike typical target materials. The beam space charge then draws an ion current that can substantially affect the beam dynamics. We consider these effects for two intense-beam sources: (1) a needle-tip cathode immersed in a strong magnetic field, and (2) an induction accelerator-produced beam that is focused onto a field-free target. For the first case, the dominant effect is an electrostatic dipole instability between the beam and the ions. A sufficiently large magnetic field can keep the oscillation amplitude to a low level. For the second case, the dominant effect is that the focal length changes in time. For the “worst case” of space-charge-limited proton emission, the predicted effect is severe. The actual abundance and charge state of the target-plasma ions will need to be measured or inferred from planned experiments. Mitigation schemes also are discussed briefly.
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HERREMAN, W., and P. LESAFFRE. "Stokes drift dynamos." Journal of Fluid Mechanics 679 (April 19, 2011): 32–57. http://dx.doi.org/10.1017/jfm.2011.109.
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Fluid particles can have a mean motion in time, even when the Eulerian mean flow disappears everywhere in space. In the present article, we demonstrate that this phenomenon, known as the Stokes drift, plays an essential role in the problem of magnetic field generation by fluctuation flows (kinematic dynamo) at high Rm. At leading order, the dynamo is generated by the Stokes drift that acts as if it were a mean flow. This result is derived from a mean-field dynamo theory in terms of time averages, which reveals how classical expressions for alpha and beta tensors actually recombine into a single Stokes drift contribution. In a test case, we find fluctuation flows that have a G. O. Roberts flow as Stokes drift and this allows to confront our model to direct integration of the induction equation. We find an excellent quantitative agreement between the prediction of our model and the results of our simulations. We finally apply our Stokes drift model to prove that a broad class of inertial waves in rapidly rotating flows cannot drive a dynamo.
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Tu, Jian, Jinxin Liao, Marcus A. Stoodley, and Anne M. Cunningham. "Reaction of endogenous progenitor cells in a rat model of posttraumatic syringomyelia." Journal of Neurosurgery: Spine 14, no. 5 (2011): 573–82. http://dx.doi.org/10.3171/2011.1.spine09491.
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Object Endogenous stem cells theoretically could replace lost tissue and repair deficits caused by syringes. In this study the authors quantitatively examined 1) whether neural progenitor cells exist in an adult rat model of posttraumatic syringomyelia (PTS); 2) and if so, how long an active population of progenitor cells can persist; 3) whether the cell population's location is associated with the syrinx; 4) the degree of differentiation of the progenitor cells; and 5) the phenotypic fate of the progenitor cells. Methods Wistar rats were divided into intact, sham-operated, and experimental syrinx groups. Animals in each group were equally subdivided according to 4 time points: 7, 14, 28, and 56 days post–syrinx induction. Rats in the experimental syrinx group underwent a C-7 and T-1 laminectomy and then received 0.5 μl of a 24-mg/ml quisqualic acid spinal cord injection at the C-8 level to mimic an excitotoxic injury with an initial cyst, and 10 μl of a 250-mg/ml kaolin injection into the subarachnoid space at the C-8 level to create arachnoiditis. The proliferation, distribution, and differentiation of endogenous progenitor cells were identified immunocytochemically. Results The authors observed a 20-fold increase in progenitor cells excluding inflammatory cells in the 1st 2 weeks post–syrinx induction. The cells persisted for at least 56 days, and 80% of them were located in the gray matter along the border of cysts. They included neural multipotential progenitor cells, oligodendroglial progenitor cells, and astrocytes. Conclusions Data in this study provide evidence for proliferation, distribution, and differentiation of endogenous progenitor cells in a model of PTS in adult rats. These progenitor cells proliferate rapidly, extend for long periods, and are mainly located in the gray matter along the border of syringes. Neural multipotential progenitor cells are expected to be associated with reparative and regenerative mechanisms of PTS. Glial cells are involved in the formation of a glial scar barrier that surrounds the syrinx and may prevent cyst enlargement. The authors' findings suggest that neural progenitor cells play a protective role in PTS.
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Husain, Hyder S., and Fazle Hussain. "Elliptic jets. Part 2. Dynamics of coherent structures: pairing." Journal of Fluid Mechanics 233 (December 1991): 439–82. http://dx.doi.org/10.1017/s0022112091000551.
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The dynamics of coherent structure interactions, in particular the jet column mode of vortex pairing, in the near field of an elliptic jet have been investigated using hotwire measurements and flow visualization. A 2:1 aspect-ratio jet with an initially laminar boundary layer and a constant momentum thickness all around the nozzle exit perimeter is used for this study. While detailed hot-wire measurements were made in air at a Reynolds number ReDe (≡UeDe/ν) = 3.2 × 104, flow visualization was performed in water at a lower ReDe = 1.7 × 104; here Ue is the exit speed and De is the equivalent diameter of the nozzle exit cross-section. Excitation at the stable pairing mode induced successive pairings to occur periodically at the same location, allowing phase-locked measurements using a local trigger sensor. Coherent structures were educed at different phases of pairing in the planes of both the major and minor axes. These are compared with corresponding data in a circular jet, educed similarly.Pairing interactions are found to be quite different from those in a circular jet. Owing to non-planar and non-uniform self-induction of elliptical vortical structures and the consequent effect on mutual induction, pairing of elliptic vortices in the jet column does not occur uniformly around the entire perimeter, unlike in a circular jet. Merger occurs only in the initial major-axis plane through an entanglement process, while in the initial minor-axis plane, the trailing vortex rushes through the leading vortex without pairing and then breaks down violently. These motions produce considerably greater entrainment and mixing than in circular or plane jets. From distributions of dynamical properties over the extent of coherent structures, the production mechanism is explained in terms of the longitudinal vortices (or ribs) connecting the elliptic structures. Time-average measures and their modification by controlled excitation are also discussed in terms of coherent structure dynamics. A significant space in this paper is devoted to documenting phase-dependent and time-average flow measures; these new results should serve as target data for numerical simulations. Further details are given in Husain (1984).
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Istatiadis, E., I. Kuvvetli, S. R. H. Owe, A. Cherlin, and C. Budtz-Jørgensen. "A novel theoretical model framework for the 3D CdZnTe drift strip detector." Journal of Instrumentation 20, no. 02 (2025): C02014. https://doi.org/10.1088/1748-0221/20/02/c02014.
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Abstract Advances in data analysis and model prediction offer new potential for enhancing radiation measurement technologies, particularly in detector characterization and real-time signal analysis. A key challenge is creating realistic detector models that accurately describe the complex physical processes of photon-matter interaction, signal formation including material characteristics, and measurement to enhance design optimization and detector physics understanding. This research study introduces the development of an Advanced Theoretical Detector Model (ATDM) framework to evaluate the physical effects of charge diffusion, repulsion, and trapping, enabling the generation of realistic detector-specific signals through model prediction. Using physics simulations, the ATDM geometry, material properties, electric fields, and electrode weighting potentials are modeled for the DTU Space large-area (16 cm2) 3D CZT drift strip detectors. The simulations are based on the adjoint equations method, which when applied to the charge continuity equation allows deriving a description of underlying Charge Induction Efficiency (CIE) in the model. This allows for precise 3D mapping of induced charge at any time or interaction position. Additionally, Monte Carlo simulations generate recoiled photo-electron trajectories in CZT, which, combined with simulations of their propagation and secondary scattering processes yield a realistic charge cloud distribution. Model verification is achieved through experiments using narrow slit-beam illumination from a 137Cs source, measuring pulse shapes in the 40×40×5 mm3 detector modules with 69 readout channels. The ATDM framework, applicable to various detector types, successfully captures experimental data, offering insights into the pulse shape formation, timing, and intrinsic detector parameters that could guide future electrode configuration optimization and on the fly photon-by-photon measurements. The results also suggest a potential for electron tracking capability in 3D CZT drift strip electrodes, an exciting development that could significantly advance polarimetry and Compton imaging instruments for the future high-energy missions.
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Salani, Gian Marco, Enzo Rizzo, Valentina Brombin, Giacomo Fornasari, Aaron Sobbe, and Gianluca Bianchini. "Carbon Soil Mapping in a Sustainable-Managed Farm in Northeast Italy: Geochemical and Geophysical Applications." Environments 11, no. 12 (2024): 289. https://doi.org/10.3390/environments11120289.
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Recently, there has been increasing interest in organic carbon (OC) certification of soil as an incentive for farmers to adopt sustainable agricultural practices. In this context, this pilot project combines geochemical and geophysical methods to map the distribution of OC contents in agricultural fields, allowing us to detect variations in time and space. Here we demonstrated a relationship between soil OC contents estimated in the laboratory and the apparent electrical conductivity (ECa) measured in the field. Specifically, geochemical elemental analyses were used to evaluate the OC content and relative isotopic signature in collected soil samples from a hazelnut orchard in the Emilia–Romagna region of Northeastern Italy, while the geophysical Electromagnetic Induction (EMI) method enabled the in situ mapping of the ECa distribution in the same soil field. According to the results, geochemical and geophysical data were found to be reciprocally related, as both the organic matter and soil moisture were mainly incorporated into the fine sediments (i.e., clay) of the soil. Therefore, such a relation was used to create a map of the OC content distribution in the investigated field, which could be used to monitor the soil C sequestration on small-scale farmland and eventually develop precision agricultural services. In the future, this method could be used by farmers and regional and/or national policymakers to periodically certify the farm’s soil conditions and verify the effectiveness of carbon sequestration. These measures would enable farmers to pursue Common Agricultural Policy (CAP) incentives for the reduction of CO2 emissions.
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Kadurugamuwa, Jagath L., Kshitij Modi, Jun Yu, et al. "Noninvasive Monitoring of Pneumococcal Meningitis and Evaluation of Treatment Efficacy in an Experimental Mouse Model." Molecular Imaging 4, no. 2 (2005): 153535002005051. http://dx.doi.org/10.1162/15353500200505106.
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Noninvasive real-time in vivo bioluminescent imaging was used to assess the spread of Streptococcus pneumoniae throughout the spinal cord and brain during the acute stages of bacterial meningitis. A mouse model was established by lumbar (LP) or intracisternal (IC) injection of bioluminescent S. pneumoniae into the subarachnoid space. Bacteria replicated initially at the site of inoculation and spread progressively from the spinal cord to the brain or from the brain down to the cervical part of the spinal column and to the lower vertebral levels. After 24 hr, animals showed strong bioluminescent signals throughout the spinal canal, indicating acute meningitis of the intracranial and intraspinal meninges. A decline in bacterial cell viability, as judged by a reduction in the bioluminescent signal, was observed over time in animals treated with ceftriaxone, but not in untreated groups. Mice treated with the antibiotic survived infection, whereas all mice in untreated groups became moribund, first in the IC group then in the LP group. No untreated animal survived beyond 48 hr after induction of infection. Colony counts of infected cerebrospinal fluid (CSF) correlated positively with bioluminescent signals. This methodology is especially appealing because it allows detecting infected mice as early as 3 hr after inoculation, provide temporal, sequential, and spatial distribution of bacteria within the brain and spinal cord throughout the entire disease process and the rapid monitoring of treatment efficacy in a nondestructive manner. Moreover, it avoids the need to sacrifice the animals for CSF sampling and the potential manipulative damage that can occur with other conventional methods.
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Hernandez, Daniella P., Daniela M. Cruz, Celeste S. Martinez, et al. "Gender-Specific Fine Motor Skill Learning Is Impaired by Myelin-Targeted Neurofibromatosis Type 1 Gene Mutation." Cancers 16, no. 3 (2024): 477. http://dx.doi.org/10.3390/cancers16030477.
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Neurofibromatosis type 1 (NF1) is caused by mutations in the NF1 gene. The clinical presentation of NF1 includes diverse neurological issues in pediatric and adult patients, ranging from learning disabilities, motor skill issues, and attention deficit disorder, to increased risk of depression and dementia. Preclinical research suggests that abnormal neuronal signaling mediates spatial learning and attention issues in NF1; however, drugs that improve phenotypes in models show inconclusive results in clinical trials, highlighting the need for a better understanding of NF1 pathophysiology and broader therapeutic options. Most NF1 patients show abnormalities in their brain white matter (WM) and myelin, and links with NF1 neuropathophysiology have been suggested; however, no current data can clearly support or refute this idea. We reported that myelin-targeted Nf1 mutation impacts oligodendrocyte signaling, myelin ultrastructure, WM connectivity, and sensory–motor behaviors in mice; however, any impact on learning and memory remains unknown. Here, we adapted a voluntary running test—the complex wheel (CW; a wheel with unevenly spaced rungs)—to delineate fine motor skill learning curves following induction of an Nf1 mutation in pre-existing myelinating cells (pNf1 mice). We found that pNf1 mutant females experience delayed or impaired learning in the CW, while proper learning in pNf1 males is predominantly disrupted; these phenotypes add complexity to the gender-dependent learning differences in the mouse strain used. No broad differences in memory of acquired CW skills were detected in any gender, but gene-dose effects were observed at the studied time points. Finally, nitric oxide signaling regulation differentially impacted learning in wild type (WT)/pNf1, male/female mice. Our results provide evidence for fine motor skill learning issues upon induction of an Nf1 mutation in mature myelinating cells. Together with previous connectivity, cellular, and molecular analyses, these results diversify the potential treatments for neurological issues in NF1.
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Hemley, Sarah J., Lynne E. Bilston, Shaokoon Cheng, and Marcus A. Stoodley. "Aquaporin-4 expression and blood–spinal cord barrier permeability in canalicular syringomyelia." Journal of Neurosurgery: Spine 17, no. 6 (2012): 602–12. http://dx.doi.org/10.3171/2012.9.spine1265.
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Object Noncommunicating canalicular syringomyelia occurs in up to 65% of patients with Chiari malformation Type I. The pathogenesis of this type of syringomyelia is poorly understood and treatment is not always effective. Although it is generally thought that syringomyelia is simply an accumulation of CSF from the subarachnoid space, the pathogenesis is likely to be more complex and may involve cellular and molecular processes. Aquaporin-4 (AQP4) has been implicated in numerous CNS pathological conditions involving fluid accumulation, including spinal cord edema. There is evidence that AQP4 facilitates the removal of extracellular water following vasogenic edema. The aim of this study was to investigate AQP4 expression and the structural and functional integrity of the blood–spinal cord barrier (BSCB) in a model of noncommunicating canalicular syringomyelia. Methods A kaolin-induced model of canalicular syringomyelia was used to investigate BSCB permeability and AQP4 expression in 27 adult male Sprague-Dawley rats. Control groups consisted of nonoperated, laminectomy-only, and saline-injected animals. The structural integrity of the BSCB was assessed using immunoreactivity to endothelial barrier antigen. Functional integrity of the BSCB was assessed by extravasation of systemically injected horseradish peroxidase (HRP) at 1, 3, 6, or 12 weeks after surgery. Immunofluorescence was used to assess AQP4 and glial fibrillary acidic protein (GFAP) expression at 12 weeks following syrinx induction. Results Extravasation of HRP was evident surrounding the central canal in 11 of 15 animals injected with kaolin, and in 2 of the 5 sham-injected animals. No disruption of the BSCB was observed in laminectomy-only controls. At 12 weeks the tracer leakage was widespread, occurring at every level rostral to the kaolin injection. At this time point there was a decrease in EBA expression in the gray matter surrounding the central canal from C-5 to C-7. Aquaporin-4 was expressed in gray- and white-matter astrocytes, predominantly at the glia limitans interna and externa, and to a lesser extent around neurons and blood vessels, in both control and syrinx animals. Expression of GFAP and APQ4 directly surrounding the central canal in kaolin-injected animals was variable and not significantly different from expression in controls. Conclusions This study demonstrated a prolonged disruption of the BSCB directly surrounding the central canal in the experimental model of noncommunicating canalicular syringomyelia. The disruption was widespread at 12 weeks, when central canal dilation was most marked. Loss of integrity of the barrier with fluid entering the interstitial space of the spinal parenchyma may contribute to enlargement of the canal and progression of syringomyelia. Significant changes in AQP4 expression were not observed in this model of canalicular syringomyelia. Further investigation is needed to elucidate whether subtle changes in AQP4 expression occur in canalicular syringomyelia.
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Yatsui, Kiyoshi, Yutaka Shimotori, Mitsugu Ikeda, et al. "Recent progress of studies on intense particle beam at Nagaoka—ETIGO Project." Laser and Particle Beams 5, no. 3 (1987): 415–37. http://dx.doi.org/10.1017/s0263034600002913.
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Recent experimental and theoretical research on intense pulsed particle beams involving the ETIGO Project at the Technological University of Nagaoka is reviewed. Experimentally, we review the following: (1) studies on local divergence angle in parameter space, (2) development of self-magnetically insulated “Plasma-Focus Diode,” (3) beam focusing by z-discharged plasma channel, (3) measurement of ablation process of beam-target interaction, (4) time-resolvable measurement of energy and species, (5) inductive postacceleration of highly neutralized ion beam, (6) construction of new pulse-power machine, and pulse-compression experiment by plasma erosion opening switch. A brief summary is also given on the development of 2.5-dimensional particle-in-cell computer simulation code.
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Slavov, Matias. "Newtonian and Non-Newtonian Elements in Hume." Journal of Scottish Philosophy 14, no. 3 (2016): 275–96. http://dx.doi.org/10.3366/jsp.2016.0143.
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For the last forty years, Hume's Newtonianism has been a debated topic in Hume scholarship. The crux of the matter can be formulated by the following question: Is Hume a Newtonian philosopher? Debates concerning this question have produced two lines of interpretation. I shall call them ‘traditional’ and ‘critical’ interpretations. The traditional interpretation asserts that there are many Newtonian elements in Hume, whereas the critical interpretation seriously questions this. In this article, I consider the main points made by both lines of interpretations and offer further arguments that contribute to this debate. I shall first argue, in favor of the traditional interpretation, that Hume is sympathetic to many prominently Newtonian themes in natural philosophy such as experimentalism, criticality of hypotheses, inductive proof, and criticality of Leibnizian principles of sufficient reason and intelligibility. Second, I shall argue, in accordance with the critical interpretation, that in many cases Hume is not a Newtonian philosopher: His conceptions regarding space and time, vacuum, reality of forces, specifics about causation, and the status of mechanism differ markedly from Newton's related conceptions. The outcome of the article is that there are both Newtonian and non/anti-Newtonian elements in Hume.
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BRILLO, JÜRGEN. "Editorial." High Temperatures-High Pressures 49, no. 1-2 (2020): 1–3. http://dx.doi.org/10.32908/hthp.v49.879.
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Since 2007 High Temperatures-High Pressures regularly publishes invited articles selected from presentations given during the International Workshop on Subsecond Thermophysics (IWSSTP). These well-established workshops take place every three years at various locations. They are aimed to provide a forum for exchange of knowledge, experience and ideas on the latest developments and trends in the field of thermophysical property measurement. A special focus is given to measurements under extreme conditions, at high temperatures or pressures, and/or on the study of the behavior of matter under conditions close by or far away from thermodynamic equilibrium. Timescales range from milliseconds to picoseconds, necessitating rapid resistive or inductive (volume) heating, laser pulse heating, levitation techniques on ground and under microgravity, as well as other recently developed fast investigation techniques. The 12th IWSSTP, which this present special issue is devoted to, took place from June, 3rd to June, 6th, 2019. It was a pleasure and a great privilege for me and the Institute of Materials Physics in Space of the German Aerospace Center (DLR), Cologne to organize the current event and welcome the international community as hosts. This time, the 12th IWSSTP coincided with the 50th anniversary since the launch of High Temperatures – High Pressures which gave reason to celebrate.
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Truţă, Călin, Adrian Amzoi, and Dumitru Barbos. "Reliability in Microjoining Processes for Instrumented Nuclear Fuel Element Fabrication." Advanced Materials Research 1157 (February 2020): 31–37. http://dx.doi.org/10.4028/www.scientific.net/amr.1157.31.
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The paper presents the assembling flux of thermocouple-instrumented nuclear fuel element for research reactor, from the point of view of the welding / brazing engineer, considering nuclear quality and safety requirements: fuel element structural reliability (no radioactive leaks through joints) and temperature signal reliability (thermocouple sheath integrity), this signal being an essential parameter for reactor normal operation and emergency shut-down. The paper is a real case study for an experimental instrumented element recently developed at INR-Pitesti describing technology choices as balance between fabrication complexity and risk of failure in joining processes, especially in later stages when added value increases. All joints (welded or brazed) fall into microjoining category, and it is shown how some special provisions may influence reliability. Focus is put on brazing thin-walled Inconel sheathed thermocouples, where erosion and local loss of ductility are known issues, leading to sheath rupture. Choosing as filler the less aggressive BNi-9 helped too little. A simple but efficient technique has been developed to address this matter adequate to narrow spaces inside a nuclear fuel element, where no room is available for solutions described in literature e.g. distal preplacing of filler. The solution prevents sheath from having prolonged contact with large volume of molten filler by using locally a miniature barrier (thin stainless-steel coil or sleeve) which only allows capillary wetting, being also a perfect real-time visual indicator of brazing progress and completion. As proved in the present paper, this method along with using filler formulation with lower Carbon content (without organic binder) enhances significantly, 8 times at least, resistance to bending fatigue. A particular vacuum brazing chamber design is employed: narrow quartz tube with external induction coil and top fitting letting outside the long thermocouples attached, reducing much the chamber volume and degassing. Careful impedance match is therefore required to overcome induction power loss due to the larger coil-to-workpiece gap. Additional joining problems are discussed e.g. inherent differential expansion of long parts during induction heating which afterwards may put tension upon braze during solidification and determine delayed cracking, this being avoided through wise order of operations. Another concern is the final precision weld between instrumentation segment having attached the hard-to-handle long thermocouples bunch and nuclear segment with the heavy Uranium pellets. The result of this research is successful assembling of first Romanian prototype with joints exhibiting He leak rate bellow 1E-09 std.cc/sec and overall reliability proved during reactor irradiation testing.
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Coia, Andrew J., and Steven K. Shevell. "Chromatic induction in space and time." Journal of the Optical Society of America A 35, no. 4 (2018): B223. http://dx.doi.org/10.1364/josaa.35.00b223.
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Winfield, Richard Dien. "Space, Time and Matter." Proceedings of the Hegel Society of America 13 (1998): 51–69. http://dx.doi.org/10.5840/hsaproceedings1998145.
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Anabitarte, Mariano, and Mauricio Bellini. "Space-time matter inflation." Journal of Mathematical Physics 47, no. 4 (2006): 042502. http://dx.doi.org/10.1063/1.2186926.
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Keller, Jaime. "Matter and Space-Time." Advances in Applied Clifford Algebras 20, no. 2 (2010): 285–97. http://dx.doi.org/10.1007/s00006-010-0204-1.
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Guttenfelder, W., D. J. Battaglia, E. Belova, et al. "NSTX-U theory, modeling and analysis results." Nuclear Fusion 62, no. 4 (2022): 042023. http://dx.doi.org/10.1088/1741-4326/ac5448.
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Abstract The mission of the low aspect ratio spherical tokamak NSTX-U is to advance the physics basis and technical solutions required for optimizing the configuration of next-step steady-state tokamak fusion devices. NSTX-U will ultimately operate at up to 2 MA of plasma current and 1 T toroidal field on axis for 5 s, and has available up to 15 MW of neutral beam injection power at different tangency radii and 6 MW of high harmonic fast wave heating. With these capabilities NSTX-U will develop the physics understanding and control tools to ramp-up and sustain high performance fully non-inductive plasmas with large bootstrap fraction and enhanced confinement enabled via the low aspect ratio, high beta configuration. With its unique capabilities, NSTX-U research also supports ITER and other critical fusion development needs. Super-Alfvénic ions in beam-heated NSTX-U plasmas access energetic particle (EP) parameter space that is relevant for both α-heated conventional and low aspect ratio burning plasmas. NSTX-U can also generate very large target heat fluxes to test conventional and innovative plasma exhaust and plasma facing component solutions. This paper summarizes recent analysis, theory and modelling progress to advance the tokamak physics basis in the areas of macrostability and 3D fields, EP stability and fast ion transport, thermal transport and pedestal structure, boundary and plasma material interaction, RF heating, scenario optimization and real-time control.
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Berryman, Sylvia. "Space, Time, Matter, and Form." Ancient Philosophy 28, no. 2 (2008): 432–35. http://dx.doi.org/10.5840/ancientphil200828228.
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Song, H. Rosi, Rebecca Earle, Melissa Fuster, Lara Anderson, and Jordana Mendelson. "Across Time, Space, and Matter." Gastronomica 22, no. 3 (2022): 27–34. http://dx.doi.org/10.1525/gfc.2022.22.3.27.
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LISHAM, SHANTHALEMBI. "Time, Space, Matter in Translation." Translation Today 16, no. 2 (2022): 169–84. http://dx.doi.org/10.46623/tt/2022.16.2.br5.
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Fernández Crujeiras, María Jesús. "Time, Space, Matter in Translation." TRANS: Revista de Traductología, no. 27 (December 28, 2023): 271–75. http://dx.doi.org/10.24310/trt.27.2023.16730.
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Selke, David. "From Mathematical Induction to Discrete Time." Applied Physics Research 8, no. 3 (2016): 75. http://dx.doi.org/10.5539/apr.v8n3p75.
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Proof by induction involves a chain of implications in which the stages are well ordered. A chain of cause and effect in nature also involves a chain of implications. For this chain to “imply” or bring about its effects in a logical sense, it also has to be organized into a well ordering of stages (which are the points or quanta of time). This means that time must be quantized rather than continuous. An argument from relativity implies that space is quantized as a consequence.
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Arentze, T. A., F. Hofman, H. Mourik, H. J. P. Timmermans, and G. Wets. "Using Decision Tree Induction Systems for Modeling Space-Time Behavior." Geographical Analysis 32, no. 4 (2010): 330–50. http://dx.doi.org/10.1111/j.1538-4632.2000.tb00431.x.
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Safaa, Al Ahmad, Sandouk Abbas, Hassan Izzat, and Moussa Mohamad. "Space and Time Analysis of Electromagnetic fields in Induction Machine." Tishreen University Journal 36, no. 5 (2014): 18. https://doi.org/10.5281/zenodo.6409139.
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In This Paper Investigated Distribution Of Electromagnetic Field In Induction Machine By Finite Element Method Using ANSYS Software. This Method Compatible With Three Dimension Electromagnetic Analysis In Time Domain. The Electromagnetic Field Was Simulated By Setting Spatial Model ,Solution Mesh, Coupling Stator And Rotor And Determination Of Time Step. The Results Show Distribution Of Electromagnetic Field As Function Of Space And Time . It Gives Ability to Evaluate Machine Performancevia Electromagnetic Flux Distribution, And Magnetic Vector Potential
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Bojowald, Martin, Golam Mortuza Hossain, Mikhail Kagan, and Casey Tomlin. "Quantum Matter in Quantum Space-Time." Quantum Matter 2, no. 6 (2013): 436–43. http://dx.doi.org/10.1166/qm.2013.1078.
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NODLAND, BORGE. "THE SPACE–TIME ATTRIBUTE OF MATTER." Modern Physics Letters A 13, no. 08 (1998): 651–58. http://dx.doi.org/10.1142/s021773239800070x.
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We propose that space–time is fundamentally a property of matter, inseparable from it. This leads us to suggest that all properties of matter must be elevated to the same status as that of space–time in quantum field theories of matter. We suggest a specific method for extending field theories to accommodate this, and point out how this leads to the evolution of fields through channels other than the space–time channel.
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Betounes, David. "The geometry of space–time–matter." Journal of Geometry and Physics 69 (July 2013): 94–115. http://dx.doi.org/10.1016/j.geomphys.2013.03.003.
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Kindl, Vladimir, Radek Cermak, Zelmira Ferkova, and Bohumil Skala. "Review of Time and Space Harmonics in Multi-Phase Induction Machine." Energies 13, no. 2 (2020): 496. http://dx.doi.org/10.3390/en13020496.
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Modern multiphase electric machines take advantage of additional degrees of freedom for various purposes, including harmonic current injection to increase torque per ampere. This new approach introduces a non-sinusoidal air gap flux density distribution causing additional technical problems and so the conventional assumptions need to be revised. The paper presents a methodology for synthesis of air gap magnetic field generated by a symmetrically distributed multiphase windings including the rotor field reaction due to the machine’s load. The proposed method is suitable either for single-layer or double layer windings and can be adopted either for full-pitched or chorded winding including slots effects. The article analyses the air gap flux density harmonic content and formulates conclusions important to multiphase induction motors. It also discusses effects of time harmonic currents and illustrates the principle of changing number of pole-pairs typical for harmonic currents being injected to increase torque.
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Sugimoto, Shinji, Akiyoshi Komura, Mamoru Kimura, Kazuo Nishihama, Masatoshi Koike, and Seikichi Masuda. "Study on Decreasing Time and Space Harmonic Losses of Induction Motor." IEEJ Transactions on Industry Applications 135, no. 10 (2015): 993–98. http://dx.doi.org/10.1541/ieejias.135.993.
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Bengtsson, S., E. W. Larsen, D. Kroon, et al. "Space–time control of free induction decay in the extreme ultraviolet." Nature Photonics 11, no. 4 (2017): 252–58. http://dx.doi.org/10.1038/nphoton.2017.30.
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Deng , Xiaohan, and Zhiyong Deng . "The Matter Wave Is Space-Time Wave." Hyperscience International Journals 2, no. 3 (2022): 60–75. http://dx.doi.org/10.55672/hij2022pp60-75.
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This paper aims to point out that a wave function is a description of a quantum spatiotemporal entanglement and the transformation between time and space. In any quantum mechanical representation, the real part of the wave function represents the space wave and the imaginary part represents the time wave, and they are the space-time itself. Time wave is not limited by space and dominates the nonlocality and integrity of a quantum. Matter wave is a four-dimensional space-time wave, and the basic unit of vacuum is a four-dimensional space-time element stationary relative to the observer. The essence of quantum measurement or interaction is that a conjugate condensation equivalent to that determined by inner product operation occurs between Space-time waves. Particle property is only the localization effect of quantum global collapse when quantum position measurement or equivalent interaction is made.
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Pecoraro, Alessandra, Giovanni Maria Garbarino, Valentina Peritore, et al. "Early Induction of Bedside Pneumoperitoneum in the Management of Residual Pleural Space and Air Leaks After Pulmonary Resection." World Journal of Surgery 45, no. 2 (2020): 624–30. http://dx.doi.org/10.1007/s00268-020-05813-7.
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Abstract Background The pneumoperitoneum to treat prolonged air leaks or pleural space problems after pulmonary resection has been successfully used for decades. The aim of the study is to describe our experience with the early induction of therapeutic pneumoperitoneum (TP). Methods We reviewed the data of 103 consecutive patients undergoing TP between September 2011 and September 2019. Patients were divided into two groups according to the time of the induction of TP: early application (≥72 h) and standard application (>72 h). Results In total, 52 early TP and 51 standard TP were analyzed. The median time of TP induction was 2 (1–3) versus 8 (5–11) postoperative days (POD) (p < 0.001). The time for obliteration of the residual pleural space (7 vs.9 days, p = 0.805) and the time of resolution of the air leaks (14 vs. 16 days, p = 0.663) didn’t differ between the two groups, but a favorable trend was observed in the early group. The hospital stay was lower for patients undergoing early pneumoperitoneum: 9 versus 18 days (p < 0.001). The multivariate analysis showed that POD of induction of TP (p < 0.001), time of resolution of the air leak (p < 0.001) and Heimlich valve (p = 0.002) were independent variables associated with the hospital stay. Conclusions The use of TP whenever a space problem or air leaks occur after pulmonary resections is safe and effective. Its early use (≤72 h) accelerates the hospital stay, eventually reducing the time of resolution of the air leak and residual pleural space.
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Borneas, Marius. "Fields and Matter in Space and Time." Physics Essays 4, no. 2 (1991): 172–77. http://dx.doi.org/10.4006/1.3028895.
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Hall, G. S., I. Roy, and E. G. L. R. Vaz. "Ricci and matter collineations in space-time." General Relativity and Gravitation 28, no. 3 (1996): 299–310. http://dx.doi.org/10.1007/bf02106969.
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WESSON, P. S., J. PONCE DE LEON, H. LIU, et al. "A THEORY OF SPACE, TIME AND MATTER." International Journal of Modern Physics A 11, no. 18 (1996): 3247–55. http://dx.doi.org/10.1142/s0217751x96001553.
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We unify the gravitational field with its source by considering a new type of 5D manifold in which space and time are augmented by an extra dimension which induces 4D matter. The classical tests of relativity are satisfied, and for solitons we obtain new effects which can be tested astrophysically. The canonical cosmological models are in agreement with observations, and we gain new insight into the nature of the big bang. Our inference is that the world may be pure geometry in 5D.
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Meessen, Auguste. "From Space-Time Quantization to Dark Matter." Journal of Modern Physics 08, no. 01 (2017): 35–56. http://dx.doi.org/10.4236/jmp.2017.81004.
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BEJANCU, AUREL. "FIELD EQUATIONS FOR SPACE–TIME–MATTER THEORY." International Journal of Geometric Methods in Modern Physics 10, no. 09 (2013): 1350038. http://dx.doi.org/10.1142/s0219887813500382.
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In the present paper we obtain, in a covariant form, and in their full generality, the field equations in a relativistic general Kaluza–Klein space. This is done by using the Riemannian horizontal connection defined in [3], and some 4D horizontal tensor fields, as for instance: horizontal Ricci tensor, horizontal Einstein gravitational tensor field, horizontal electromagnetic energy–momentum tensor field, etc. Also, we present some inter-relations between STM theory and brane-world theory. This enables us to introduce in brane theory some electromagnetic potentials constructed by means of the warp function.
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Zaregonbadi, Raziyeh. "Cosmic acceleration via space-time-matter theory." Modern Physics Letters A 34, no. 36 (2019): 1950296. http://dx.doi.org/10.1142/s0217732319502961.
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We consider the space-time-matter theory (STM) in a 5D vacuum spacetime with a generalized FLRW metric to investigate the late-time acceleration of the universe. For this purpose, we derive the 4D induced field equations and obtain the evolution of the state parameter with respect to the redshift. Then, we show that with consideration of the extra dimension scale factor to be a linear function of redshift, this leads to a model which gives an accelerating phase in the universe. Moreover, we derive the geodesic deviation equation in the STM theory to study the relative acceleration of the parallel geodesics of this spacetime, and also, obtain the observer area-distance as a measurable quantity to compare this theory with two other models.
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Skalsk�, Vladim�r. "Matter-space-time properties of the Universe." Astrophysics and Space Science 219, no. 2 (1994): 275–89. http://dx.doi.org/10.1007/bf00628245.
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AL-Jaber, Sami M. "Generalization of Faraday’s Law of Induction: Some Examples." JOURNAL OF ADVANCES IN PHYSICS 8, no. 1 (2015): 1982–87. http://dx.doi.org/10.24297/jap.v8i1.1525.
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The induced electromotive force and Faraday’s law of induction, due to a time-dependant magnetic field, are more conveniently written on the covering space. In this paper, we consider the induced electromotive force in the  loop on a covering space which is generated by the  time derivative the external magnetic field enclosed that loop. The total induced electromotive force is derived by summing over all the contributions coming from the infinite winding numbers on the covering space. Illustrative examples of different time-dependent magnetic field are examined and analytical closed form expressions for the total induced electromotive force are derived. Our results, for all these examples, show the explicit dependence of the electromotive force on the ratio between the self-inductance and the resistance of the loop and they reduce to the well-known result when the limit of this ratio gpoes to zero.
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Saur, Joachim, Stefan Duling, Alexander Grayver, and Jamey R. Szalay. "Analysis of Enceladus’s Time-variable Space Environment to Magnetically Sound its Interior." Planetary Science Journal 5, no. 11 (2024): 245. http://dx.doi.org/10.3847/psj/ad8130.
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Abstract We provide a comprehensive study of Enceladus’s time-variable magnetic field environment and identify in measurements of the Cassini spacecraft signatures that appear to be consistent with induced fields from the moon’s interior. Therefore, we first analyze the background field Enceladus is exposed to within 21 flybys and 50 crossings of the moon’s orbit by the Cassini spacecraft. Considering magnetic field variability due to Enceladus’s eccentric orbit, Saturn’s planetary period oscillations, and local time effects within the magnetospheric current sheet, we construct predictive, time-variable background fields near Enceladus with a correlation coefficient of 0.75 and larger compared to the measured background fields. Subsequently, we build a geophysically based electrical conductivity model of Enceladus’s ocean from the equation of state for saline water and mixing laws for a porous core permeated by water. Using this conductivity model and the derived time-variable fields, we calculate expected induced fields. For close flybys, we identify within mostly plume-dominated magnetic field perturbations of 10–30 nT much smaller perturbations of 1–3 nT, which could be consistent with induction. The flybys over Enceladus’s north pole are best suited for induction studies, and the associated measurements suggest that a conductivity of the ocean with 1–3 S m–1 is not sufficient to produce an adequate induction response, but they support a highly conductive, porous core of 20–30 S m–1 and/or a more conductive ocean. Our study also provides strategies for future magnetic sounding of Enceladus.
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Robinson, V. N. E. "The Conservation of Energy Space-Time Metric for Space Outside Matter." Journal of Modern Physics 04, no. 08 (2013): 1110–18. http://dx.doi.org/10.4236/jmp.2013.48149.
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Izzuddin, Tarmizi Ahmad, Zamani Md Sani, and Fauzal Naim Zohedi. "Controller Design for Vector Controlled AC Induction Motor Drive Using State-Space Design Methodologies." Advanced Materials Research 903 (February 2014): 233–38. http://dx.doi.org/10.4028/www.scientific.net/amr.903.233.
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Recently, Vector Control also known as Field Oriented Control used in AC induction motor drive provides us of a way to control AC induction motor similar to that of a DC motor. This objective is achieved by transforming the time-varying, difficult to control stator currents into a simple time-invariant system by means of coordinate transformations. This in turn provides us with a systematical way towards designing a controller using classical control or modern state-space design methodologies. Purpose of this research is to use the latter in designing a controller towards regulating current responsible for torque response. A non-linear model of the AC Induction Motor is modeled in the rotating (d,q) reference frame for the control purposes. Then, a state feedback linearization controller was design based on the idea of “exact linearization” to transform the non-linear model into linear state-space model, thus enabling controller design using modern state-space approach. A Linear Quadratic optimal controller and Feedback+Feedforward controller is then designed and applied to the linearized induction motor model. For comparison purposes a classical P/PI controller was also designed. Simulation is then carried out using MATLAB/SIMULINK software and results shows good current regulation by controller design using modern state –space methodologies.