Zeitschriftenartikel: „Photon rockets“

1

Damour, Thibault. „Photon rockets and gravitational radiation“. Classical and Quantum Gravity 12, Nr. 3 (01.03.1995): 725–37. http://dx.doi.org/10.1088/0264-9381/12/3/011.

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2

PODOLSKÝ, JIŘÍ. „PHOTON ROCKETS MOVING ARBITRARILY IN ANY DIMENSION“. International Journal of Modern Physics D 20, Nr. 03 (März 2011): 335–60. http://dx.doi.org/10.1142/s0218271811018846.

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A family of explicit exact solutions of Einstein's equations in four and higher dimensions is studied which describes the gravitational field of an object accelerating due to an anisotropic emission of photons. It is possible to prescribe an arbitrary motion, so that the acceleration of such photon rocket need not be uniform — both its magnitude and direction may vary with time. Except at the location of the rocket the space–times have no curvature singularities, and topological defects like cosmic strings are also absent. Any value of a cosmological constant is allowed. We investigate some particular examples of motion, namely a straight flight and a circular trajectory, and we derive the corresponding radiation patterns and the mass loss of the rockets. We also demonstrate the absence of "gravitational aberration" in such space–times. This interesting member of the higher-dimensional Robinson–Trautman class of pure radiation space–times of algebraic Type D generalizes the class of Kinnersley's solutions that has long been known in four-dimensional general relativity.

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3

Ge, Huabin, Mingxing Luo, Qiping Su, Ding Wang und Xiao Zhang. „Bondi-Sachs metrics and photon rockets“. General Relativity and Gravitation 43, Nr. 10 (01.06.2011): 2729–42. http://dx.doi.org/10.1007/s10714-011-1197-3.

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4

Dain, Sergio, Osvaldo M. Moreschi und Reinaldo J. Gleiser. „Photon rockets and the Robinson - Trautman geometries“. Classical and Quantum Gravity 13, Nr. 5 (01.05.1996): 1155–60. http://dx.doi.org/10.1088/0264-9381/13/5/026.

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5

Cornish, F. H. J. „Robinson-Trautman radiating metrics with zero news and photon rockets“. Classical and Quantum Gravity 17, Nr. 18 (05.09.2000): 3945–50. http://dx.doi.org/10.1088/0264-9381/17/18/425.

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6

Gallo, Emanuel, und Osvaldo M. Moreschi. „Modeling the dynamics of black holes through balanced equations of motion in the null gauge“. International Journal of Geometric Methods in Modern Physics 16, Nr. 09 (September 2019): 1950131. http://dx.doi.org/10.1142/s0219887819501317.

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We develop further the general framework for modeling the dynamics of the motion of black holes, presented in [E. Gallo and O. M. Moreschi, Modeling the dynamics of black holes through balanced equations of motion, Int. J. Geom. Meth. Mod. Phys. 16(3) (2019) 1950034], by employing a convenient null gauge, in general relativity, for the construction of the balanced equations of motion. This null gauge has the property that the asymptotic structure is intimately related to the interior one; in particular there is a strong connection between the field equations and the balanced equations of motion. Our work is very related to what we have called “Robinson–Trautman (RT) geometries” [S. Dain, O. M. Moreschi and R. J. Gleiser, Photon rockets and the Robinson–Trautman geometries, Class. Quantum Grav. 13(5) (1996) 1155–1160] in the past. These geometries are used in the sense of the general framework, we have presented in [E. Gallo and O. M. Moreschi, Modeling the dynamics of black holes through balanced equations of motion, Int. J. Geom. Meth. Mod. Phys. 16(3) (2019) 1950034]. We present the balanced equations of motion in second order of the acceleration. We solve the required components of the field equation at their respective required orders, [Formula: see text] and [Formula: see text], in terms of the gravitational constant. We indicate how this approach can be extended to higher orders.

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Dariusz Stanisław Sobolewski, Michał Amadeusz Sobolewski, Marek Juliusz Sobolewski, Joanna Paulina Sobolewska und Natalia Julia Sobolewska. „New Generations of Rocket Engines“. JOURNAL OF ADVANCES IN PHYSICS 17 (22.05.2020): 322–46. http://dx.doi.org/10.24297/jap.v17i.8747.

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The article, based on mathematical model of the space and particles revealed in "Theory of Space" (Sobolewski D. S., Theory of Space, 2016) (Sobolewski D. S., Theory of Space, 2017) and the description of the propagation of photons stated in publication entitled “Geometry of the Dark Matter and Preliminary Analysis of Alpha and Beta Photons’ Properties Based on Theory of Space” (Sobolewski, Sobolewski i Sobolewski, 2017), describes transverse waves propagating in space, including gravitational, fluctuating and matter waves. In particular, it focuses on waves of matter in which orientation of the spatial channels, connecting four-dimensional boundary hypersurfaces and , had been stabilised. For this type of the wave of matter the minimum energy value for deformation of boundary hypersurfaces of the matter waves has been appointed, which is smaller by several orders of magnitude than energy needed to change the orientation of vertical disturbances of space which connect four-dimensional boundary hypersurfaces and, The obtained results were used to introduce a new classification of rocket engines and to provide examples of their implementation. Furthermore, the article demonstrates first attempts to construct a rocket engine of the new type, including description of the principle of operation of the engine, which is subject of patent application entitled "HTS Photonic Rocket Engine" (Poland Patent nr P.421517, 2017), as well as presents an example of spacecraft shell implementation, which enables stabilization of orientation of its spatial channels. The Article thus reveals new perspectives for interplanetary travel through significant increase in spacecraft velocities, while simultaneously reducing the energy required to achieve them. In addition, the article describes interaction of photons with the boundary hypersurface , while determining the change in photon frequency depending on its curvature .

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8

Bonnor, W. B. „The photon rocket“. Classical and Quantum Gravity 11, Nr. 8 (01.08.1994): 2007–12. http://dx.doi.org/10.1088/0264-9381/11/8/008.

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9

Bonnor, W. B. „Another photon rocket“. Classical and Quantum Gravity 13, Nr. 2 (01.02.1996): 277–82. http://dx.doi.org/10.1088/0264-9381/13/2/015.

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10

Heller, René, Guillem Anglada-Escudé, Michael Hippke und Pierre Kervella. „Low-cost precursor of an interstellar mission“. Astronomy & Astrophysics 641 (September 2020): A45. http://dx.doi.org/10.1051/0004-6361/202038687.

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The solar photon pressure provides a viable source of thrust for spacecraft in the solar system. Theoretically it could also enable interstellar missions, but an extremely small mass per cross section area is required to overcome the solar gravity. We identify aerographite, a synthetic carbon-based foam with a density of 0.18 kg m−3 (15 000 times more lightweight than aluminum) as a versatile material for highly efficient propulsion with sunlight. A hollow aerographite sphere with a shell thickness ϵshl = 1 mm could go interstellar upon submission to solar radiation in interplanetary space. Upon launch at 1 AU from the Sun, an aerographite shell with ϵshl = 0.5 mm arrives at the orbit of Mars in 60 d and at Pluto’s orbit in 4.3 yr. Release of an aerographite hollow sphere, whose shell is 1 μm thick, at 0.04 AU (the closest approach of the Parker Solar Probe) results in an escape speed of nearly 6900 km s−1 and 185 yr of travel to the distance of our nearest star, Proxima Centauri. The infrared signature of a meter-sized aerographite sail could be observed with JWST up to 2 AU from the Sun, beyond the orbit of Mars. An aerographite hollow sphere, whose shell is 100 μm thick, of 1 m (5 m) radius weighs 230 mg (5.7 g) and has a 2.2 g (55 g) mass margin to allow interstellar escape. The payload margin is ten times the mass of the spacecraft, whereas the payload on chemical interstellar rockets is typically a thousandth of the weight of the rocket. Using 1 g (10 g) of this margin (e.g., for miniature communication technology with Earth), it would reach the orbit of Pluto 4.7 yr (2.8 yr) after interplanetary launch at 1 AU. Simplistic communication would enable studies of the interplanetary medium and a search for the suspected Planet Nine, and would serve as a precursor mission to α Centauri. We estimate prototype developments costs of 1 million USD, a price of 1000 USD per sail, and a total of < 10 million USD including launch for a piggyback concept with an interplanetary mission.

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11

Lockerbie, I. D., W. S. C. Brooks, P. How und E. J. Llewellyn. „Monte-Carlo simulation of single-line resonance scattering in a rarefied gas“. Canadian Journal of Physics 69, Nr. 8-9 (01.08.1991): 1146–53. http://dx.doi.org/10.1139/p91-174.

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A Monte-Carlo simulation of single-line resonant scattering in a rarefied gas is presented and the technique is applied to the interpretation of a rocket-borne resonance-lamp experiment. The simulation examines the case of an emitting and absorbing gas at the same temperature for a number of detector and source configurations. The distance from the last scatter point, the angular distribution of the detected scattered photons, and the line shape formed by the scattered photons, at the detector, are evaluated for these different configurations. The simulation results suggest that the scattering of the detected photon occurs very near to the rocket, and not necessarily in the traditional scattering region at the intersection of the detector and emitter normals. It is observed that multiple scattering plays an important role in the number of photons detected and that the apparent gas temperature, as exhibited by the line shapes of the scattered photons, is dependent upon the configuration of the experiment. The simulation results suggest that, for a resonance-scattering experiment to measure constituent concentrations, the experimental design must optimize the return signal and minimize the effect of multiple scattering. The results also suggest that the calibration procedures for resonance-scattering experiments must be made with a physical configuration and environment that is identical to that expected in the rocket flight.

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12

Cornish, F. H. J., und B. Micklewright. „Gravitational radiation and the photon rocket“. Classical and Quantum Gravity 13, Nr. 9 (01.09.1996): 2499–503. http://dx.doi.org/10.1088/0264-9381/13/9/014.

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13

Pierse, R. „Photo Essay: Rocket Man“. IEEE Spectrum 42, Nr. 11 (2005): 22–23. http://dx.doi.org/10.1109/mspec.2005.1526901.

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14

Haug, Espen Gaarder. „The ultimate limits of the relativistic rocket equation. The Planck photon rocket“. Acta Astronautica 136 (Juli 2017): 144–47. http://dx.doi.org/10.1016/j.actaastro.2017.03.011.

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15

Pal’shin, V. D., und A. I. Tsygan. „Effect of Photon Rocket in X-ray Binaries“. International Astronomical Union Colloquium 177 (2000): 653–54. http://dx.doi.org/10.1017/s0252921100060905.

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AbstractIt is shown that X-ray binaries can be accelerated by their own radiation. It is possible if the magnetic field of a neutron star in a binary differs from the dipolar field. Asymmetric X-ray emission generated due to accretion of matter onto a neutron star surface creates an accelerating force. Its magnitude can be comparable or even larger than gravitational attraction of the binary to the Galaxy.

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Tommasini, Daniele, Angel Paredes und Humberto Michinel. „Comment on “the ultimate limits of the relativistic rocket equation. The Planck photon rocket”“. Acta Astronautica 161 (August 2019): 373–74. http://dx.doi.org/10.1016/j.actaastro.2019.01.051.

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17

Burinskii, Alexander. „Complex structure of Kerr geometry and rotating photon rocket solutions“. Classical and Quantum Gravity 20, Nr. 5 (14.02.2003): 905–12. http://dx.doi.org/10.1088/0264-9381/20/5/309.

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18

Vuillaume, T., G. Henri und P. O. Petrucci. „A stratified jet model for AGN emission in the two-flow paradigm“. Astronomy & Astrophysics 620 (28.11.2018): A41. http://dx.doi.org/10.1051/0004-6361/201731899.

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Context. High-energy emission of extragalactic objects is known to take place in relativistic jets, but the nature, the location, and the emission processes of the emitting particles are still unknown. One of the models proposed to explain the formation of relativistic ejections and their associated non-thermal emission is the two-flow model, where the jets are supposed to be composed of two different flows, a mildly relativistic baryonic jet surrounding a fast, relativistically moving electron positron plasma. Here we present the simulation of the emission of such a structure taking into account the main sources of photons that are present in active galactic nuclei (AGNs). Aims. We try to reproduce the broadband spectra of radio-loud AGNs with a detailed model of emission taking into account synchrotron and inverse-Compton emission by a relativistically moving beam of electron positron, heated by a surrounding turbulent baryonic jet. Methods. We compute the density and energy distribution of a relativistic pair plasma all along a jet, taking into account the synchrotron and inverse-Compton process on the various photon sources present in the core of the AGN, as well as the pair creation and annihilation processes. We use semi-analytical approximations to quickly compute the inverse-Compton process on a thermal photon distribution with any anisotropic angular distribution. The anisotropy of the photon field is also responsible for the bulk acceleration of the pair plasma through the “Compton rocket” effect, thus imposing the plasma velocity along the jet. As an example, the simulated emerging spectrum is compared to the broadband emission of 3C 273. Results. In the case of 3C 273, we obtain an excellent fit of the average broadband energy distribution by assuming physical parameters compatible with known estimates. The asymptotic bulk Lorentz factor is lower than what is observed by superluminal motion, but the discrepancy could be solved by assuming different acceleration profiles along the jet.

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Schmidt, Jacob B., Zane D. Schaefer, Terrence R. Meyer, Sukesh Roy, Stephen A. Danczyk und James R. Gord. „Ultrafast time-gated ballistic-photon imaging and shadowgraphy in optically dense rocket sprays“. Applied Optics 48, Nr. 4 (24.12.2008): B137. http://dx.doi.org/10.1364/ao.48.00b137.

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Vuillaume, Thomas, Gilles Henri und Pierre-Olivier Petrucci. „Influence of an AGN complex photon field on the jet bulk Lorentz factor through Compton rocket effect“. Proceedings of the International Astronomical Union 10, S313 (September 2014): 179–80. http://dx.doi.org/10.1017/s1743921315002161.

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McCoy, Jake, Ted Schultz, James Tutt, Thomas Rogers, Drew Miles und Randall McEntaffer. „A Primer for Telemetry Interfacing in Accordance with NASA Standards Using Low Cost FPGAs“. Journal of Astronomical Instrumentation 05, Nr. 01 (März 2016): 1640002. http://dx.doi.org/10.1142/s225117171640002x.

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Photon counting detector systems on sounding rocket payloads often require interfacing asynchronous outputs with a synchronously clocked telemetry (TM) stream. Though this can be handled with an on-board computer, there are several low cost alternatives including custom hardware, microcontrollers and field-programmable gate arrays (FPGAs). This paper outlines how a TM interface (TMIF) for detectors on a sounding rocket with asynchronous parallel digital output can be implemented using low cost FPGAs and minimal custom hardware. Low power consumption and high speed FPGAs are available as commercial off-the-shelf (COTS) products and can be used to develop the main component of the TMIF. Then, only a small amount of additional hardware is required for signal buffering and level translating. This paper also discusses how this system can be tested with a simulated TM chain in the small laboratory setting using FPGAs and COTS specialized data acquisition products.

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Hedin, J., M. Rapp, M. Khaplanov, J. Stegman und G. Witt. „Observations of NO in the upper mesosphere and lower thermosphere during ECOMA 2010“. Annales Geophysicae 30, Nr. 11 (28.11.2012): 1611–21. http://dx.doi.org/10.5194/angeo-30-1611-2012.

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Abstract. In December 2010 the last campaign of the German-Norwegian sounding rocket project ECOMA (Existence and Charge state Of Meteoric smoke particles in the middle Atmosphere) was conducted from Andøya Rocket Range in northern Norway (69° N, 16° E) in connection with the Geminid meteor shower. The main instrument on board the rocket payloads was the ECOMA detector for studying meteoric smoke particles (MSPs) by active photoionization and subsequent detection of the produced charges (particles and photoelectrons). In addition to photoionizing MSPs, the energy of the emitted photons from the ECOMA flash-lamp is high enough to also photoionize nitric oxide (NO). Thus, around the peak of the NO layer, at and above the main MSP layer, photoelectrons produced by the photoionization of NO are expected to contribute to, or even dominate above the main MSP-layer, the total measured photoelectron current. Among the other instruments on board was a set of two photometers to study the O2 (b1Σg+−X3Σg

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Jordan, S. D. „Line Formation and Intensity Enhancement of the He II 304Å Line in the Solar Atmosphere“. International Astronomical Union Colloquium 144 (1994): 415–20. http://dx.doi.org/10.1017/s0252921100025719.

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AbstractObservations of He II 304Å line profiles from the Goddard solar EUV sounding rocket flight of May 9, 1991 are analyzed to determine lower limits on the small scale non-thermal velocities in the regions observed. In the quiet Sun, a lower limit of 30 km/s is obtained over much of the spectrograph slit. It is argued that a sufficient fraction of the He II ions will survive in their upward motions, before collisional excitation to produce a 304Å photon, to enhance the computed line intensity up to the observed values, in contrast to earlier theoretical results that yield total line intensities generally smaller than observed values.

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Vuillaume, T., G. Henri und P. O. Petrucci. „Variation of bulk Lorentz factor in AGN jets due to Compton rocket in a complex photon field“. Astronomy & Astrophysics 581 (26.08.2015): A18. http://dx.doi.org/10.1051/0004-6361/201525972.

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25

Akkurt, I., H. T. Ozkahraman, B. Mavi und A. Akkurt. „The Photon Attenuation Coefficients and Thermal Conductivity of Volcanic Rocks“. Zeitschrift für Naturforschung A 59, Nr. 12 (01.12.2004): 888–92. http://dx.doi.org/10.1515/zna-2004-1202.

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The linear attenuation coefficient (μ cm−1) of photon propogation and the thermal conductivity have been determined for some volcanic rocks, which are commonly used materials in building constructions especially as a cladding stone. The linear attenuation coefficient calculated using XCOM is compared with the measurement. Thermal conductivity has been extracted from P-Wave velocity measured using a Pundit apparatus. The relation between thermal conductivity and the attenuation coefficient are also investigated.

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Ellingsen, Pål Gunnar, Dag Lorentzen, David Kenward, James H. Hecht, J. Scott Evans, Fred Sigernes und Marc Lessard. „Observations of sunlit N2+ aurora at high altitudes during the RENU2 flight“. Annales Geophysicae 39, Nr. 5 (24.09.2021): 849–59. http://dx.doi.org/10.5194/angeo-39-849-2021.

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Abstract. We present measurements of sunlit aurora during the launch of the Rocket Experiment for Neutral Upwelling 2 (RENU2) on the 13 December 2015, 07:34 UTC. The in situ auroral conditions coincide with those of sunlit aurora and were characterised by the 391.4 and 427.8 nm N2+ emissions. A correlation between several auroral wavelengths, as measured by a meridian-scanning photometer, was used to detect sunlit aurora and indirectly neutral upwelling. These results, based on ground data, agree well with the RENU2 measurements recorded during its pass through the sunlit polar cusp. Using in situ data from RENU2 and the solar photon flux, it was estimated that the sunlit aurora was a major part (≈40 %) of the observed 427.8 nm emission.

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France, Kevin, Keri Hoadley, Brian T. Fleming, Robert Kane, Nicholas Nell, Matthew Beasley und James C. Green. „The SLICE, CHESS, and SISTINE Ultraviolet Spectrographs: Rocket-Borne Instrumentation Supporting Future Astrophysics Missions“. Journal of Astronomical Instrumentation 05, Nr. 01 (März 2016): 1640001. http://dx.doi.org/10.1142/s2251171716400018.

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NASA’s suborbital program provides an opportunity to conduct unique science experiments above Earth’s atmosphere and is a pipeline for the technology and personnel essential to future space astrophysics, heliophysics, and atmospheric science missions. In this paper, we describe three astronomy payloads developed (or in development) by the Ultraviolet Rocket Group at the University of Colorado. These far-ultraviolet (UV) (100–160[Formula: see text]nm) spectrographic instruments are used to study a range of scientific topics, from gas in the interstellar medium (accessing diagnostics of material spanning five orders of magnitude in temperature in a single observation) to the energetic radiation environment of nearby exoplanetary systems. The three instruments, Suborbital Local Interstellar Cloud Experiment (SLICE), Colorado High-resolution Echelle Stellar Spectrograph (CHESS), and Suborbital Imaging Spectrograph for Transition region Irradiance from Nearby Exoplanet host stars (SISTINE) form a progression of instrument designs and component-level technology maturation. SLICE is a pathfinder instrument for the development of new data handling, storage, and telemetry techniques. CHESS and SISTINE are testbeds for technology and instrument design enabling high-resolution ([Formula: see text]) point source spectroscopy and high throughput imaging spectroscopy, respectively, in support of future Explorer, Probe, and Flagship-class missions. The CHESS and SISTINE payloads support the development and flight testing of large-format photon-counting detectors and advanced optical coatings: NASA’s top two technology priorities for enabling a future flagship observatory (e.g. the LUVOIR Surveyor concept) that offers factors of [Formula: see text][Formula: see text]50–100 gain in UV spectroscopy capability over the Hubble Space Telescope. We present the design, component level laboratory characterization, and flight results for these instruments.

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Al-Buriahi, Mohammed Sultan, M. I. Sayyed, Rashad A. R. Bantan und Yas Al-Hadeethi. „Nuclear Radiation Shielding Characteristics of Some Natural Rocks by Using EPICS2017 Library“. Materials 14, Nr. 16 (19.08.2021): 4669. http://dx.doi.org/10.3390/ma14164669.

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Radiation leakage is a serious problem in various technological applications. In this paper, radiation shielding characteristics of some natural rocks are elucidated. Mass attenuation coefficients (µ/ρ) of these rocks are obtained at different photon energies with the help of the EPICS2017 library. The obtained µ/ρ values are confirmed via the theoretical XCOM program by determining the correlation factor and relative deviation between both of these methods. Then, effective atomic number (Zeff), absorption length (MFP), and half value layer (HVL) are evaluated by applying the µ/ρ values. The maximum μ/ρ values of the natural rocks were observed at 0.37 MeV. At this energy, the Zeff values of the natural rocks were 16.23, 16.97, 17.28, 10.43, and 16.65 for olivine basalt, jet black granite, limestone, sandstone, and dolerite, respectively. It is noted that the radiation shielding features of the selected natural rocks are higher than that of conventional concrete and comparable with those of commercial glasses. Therefore, the present rocks can be used in various radiation shielding applications, and they have many advantages for being clean and low-cost products. In addition, we found that the EPICS2017 library is useful in determining the radiation shielding parameters for the rocks and may be used for further calculations for other rocks and construction building materials.

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Góes-Neto, Luiz Armando De Araújo, Gustavo Heringer und Alexandre Salino. „Selaginella salinoi (Selaginellaceae), a new species from Brazil“. Phytotaxa 224, Nr. 3 (02.09.2015): 291. http://dx.doi.org/10.11646/phytotaxa.224.3.8.

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A species of Selaginella from Parque Nacional do Caparaó, in Espírito Santo State, southeastern Brazil, is described as new to the science: Selaginella salinoi grows on rocks in Atlantic Rainforest vegetation at ca. 1200 m. The description includes photos of live plants and, scanning electron micrographs.

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Kita, K., T. Imamura, N. Iwagami, W. H. Morrow und T. Ogawa. „Rocket observation of atomic oxygen and night airglow: Measurement of concentration with an improved resonance fluorescence technique“. Annales Geophysicae 14, Nr. 2 (29.02.1996): 227–37. http://dx.doi.org/10.1007/s00585-996-0227-z.

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Abstract. An improved resonant fluorescence instrument for measuring atomic oxygen concentration was developed to avoid the Doppler effect and the aerodynamic shock effect due to the supersonic motion of a rocket. The shock effect is reduced by adopting a sharp wedge-shaped housing and by scanning of the detector field of view to change the distance between the scattering volume and the surface of the housing. The scanning enables us to determine absolute values of atomic oxygen concentration from relative variation of the scattered light signal due to the self-absorption. The instrument was calibrated in the laboratory, and the numerical simulation reproduced the calibration result. Using the instrument, the altitude profile of atomic oxygen concentration was observed by a rocket experiment at Uchinoura (31°N) on 28 January 1992. The data obtained from the rocket experiment were not perfectly free from the shock effect, but errors due to the effect were reduced by the data analysis procedure. The observed maximum concentration was 3.8× 1011 cm–3 at altitudes around 94 km. The systematic error is estimated to be less than ±0.7×1011 cm–3 and the relative random error is less than±0.07× 1011 cm–3at the same altitudes. The altitude profile of the OI 557.7-nm airglow was also observed in the same rocket experiment. The maximum volume emission rate was found to be 150 photons cm–3 s–1 at 94 km. The observed altitude profiles are compared with the MSIS model and other in situ observations.

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Krausová, Ivana, Jiří Mizera, Zdeněk Řanda, David Chvátil und Pavel Krist. „Instrumental Photon Activation Analysis with Short-Time Irradiation for Geochemical Research“. Minerals 11, Nr. 6 (09.06.2021): 617. http://dx.doi.org/10.3390/min11060617.

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This paper introduces instrumental photon activation analysis (IPAA) utilizing short-lived products of photonuclear reactions, mainly (γ, n) and (γ, p), initiated by bremsstrahlung from the MT-25 microtron. A rapid nondestructive IPAA method for geochemical major element analysis is introduced as a tool for the basic geochemical characterization of rocks. Procedures were developed and parameters such as beam energy and irradiation-decay-counting times optimized with a representative set of geochemical reference materials, and an optimized scheme was applied in analysis of various geological samples. A complete analytical scheme combined with long-time irradiation IPAA and the possibility of utilization of photoexcitation reactions (γ, γ′) are briefly outlined.

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RUNYON, JUSTIN B. „Two new species of Hurleyella Runyon & Robinson (Diptera: Dolichopodidae), with the first record from the Neotropics“. Zootaxa 4568, Nr. 3 (21.03.2019): 548. http://dx.doi.org/10.11646/zootaxa.4568.3.8.

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Two new species of the long-legged fly genus Hurleyella Runyon & Robinson, 2010 are described and illustrated: Hurleyella belizensis sp. nov. from Belize and Hurleyella salina sp. nov. from alkali areas of the Northern Rockies of the USA (Idaho, Montana, Wyoming). The discovery of these new species greatly extends the known distribution of Hurleyella northward in the Nearctic and southward into the Neotropics. Notes, photos of habitats, a distribution map, and a key to the four known species of Hurleyella are provided.

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Wu, X., L. Xie, D. Chen, Y. Wang, X. Wang und F. Ma. „PRELIMINARY STUDY ON THE PREVENTIVE PROTECTION OF ROCKERY IN THE MOUNTAIN RESORT BASED ON THE COMPREHENSIVE DIGITAL TECHNOLOGY“. International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLVI-M-1-2021 (28.08.2021): 859–66. http://dx.doi.org/10.5194/isprs-archives-xlvi-m-1-2021-859-2021.

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Abstract. The concept of preventive protection originates from the European heritage protection field. Nowadays, a complete knowledge system and normative reference framework have been formed in the field of museum collection cultural relics. However, it is just beginning in the field of traditional garden heritage protection. Based on the review of the theories and practices of the preventive protection of international historical building and traditional garden heritage, this paper makes a comprehensive survey, photo and modeling record of the rockery of Mountain Resort with the help of the current comprehensive digital mapping technology. Based on this, the paper combines the historical data files to carry out the comprehensive analysis and evaluation of the authenticity, destruction and safety of the present rockery; moreover, taking Jinshan as an example, the main points of digital surveying and mapping of large-scale rockery are summarized; Finally, summarize the current problems of rockery and put forward preventive protection suggestions. It is hoped that through this study, the case of preventive protection of Royal Garden heritage in Qing Dynasty will be enriched, and a new idea will be provided for the protection of Royal Garden heritage in Qing Dynasty.

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Zhao, Yue, Lijun Yang und Qingfei Fu. „Ligament characterization of atomizing non-Newtonian liquid sheets: Fractal dimension“. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, Nr. 1 (26.03.2018): 173–78. http://dx.doi.org/10.1177/0954406218756937.

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As gel propellants are increasingly used in rocket engines, non-Newtonian liquid atomization has emerged as a research subject of great interest. This paper addresses the atomization of flat sheets of aqueous xanthan gum solution, which are formed from two jets ejected from impinging injectors. Based on the experimental photos, it has been found that gel liquid sheets do not break up directly into droplets that can be characterized as spheres with Sauter mean diameter; instead, a mass of ligaments is observed. Therefore, this paper will introduce fractal dimension as a new parameter, related to the quality of atomization under these experimental conditions; and a power-law correlation between fractal dimension and Reynolds number of liquid jets has been achieved.

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Dukas, Reuven. „Effects of Predation by Bumblebee Wolves (Philanthus bicinctus, sphecidae, hymenoptera) on Bumblebees and Plants“. UW National Parks Service Research Station Annual Reports 27 (01.01.2003): 78. http://dx.doi.org/10.13001/uwnpsrc.2003.3543.

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The interactions between flowers and their pollinators have been extensively studied in ecology, evolution and conservation biology. Although predators can dramatically influence insect-flower interactions, this issue has been mostly ignored until recently. One of the best systems for quantifying the effect of predators on pollinators is that of bumblebee wolves (Philanthus bicinctus), which are sphecid wasps endemic to the American Rockies, who prey almost exclusively on bumblebees. (see photos at http://psych.mcmaster.caldukas/pred&poll.htm). Relaying on research from 45 years ago, I located a large aggregation of bumblebee wolves at Yellowstone National Park and commenced research in summer 2003.

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Selvi, Federico. „Anthyllis cytisoides L. (Fabaceae), new to the Italian native flora“. Italian Botanist 10 (25.08.2020): 25–31. http://dx.doi.org/10.3897/italianbotanist.10.55154.

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We present the first finding of Anthyllis cytisoides L. in Italy. This western Mediterranean woody species was found close to the coastline on the southwest side of Mt. Argentario in southern Tuscany, on limestone rocks within a xerophytic garrigue community of the Erico multiflorae-Rosmarinetum officinali association. A description of the plant is given along with an original iconography and photos taken in the field. The reasons for considering this population of natural origin are briefly discussed, along with the possible causes of its wide disjunction from the rest of the species range.

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Aguilar, Laura. „Human Nature“. Boom 5, Nr. 2 (2015): 22–27. http://dx.doi.org/10.1525/boom.2015.5.2.22.

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Laura Aguilar’s Nature Self Portraits treat the human body as another feature in landscapes. In the series, Aguilar positions herself in the center of her photographs, nude, often with her back to the camera. The curve of her back echoes the rocks, her black hair in the wind recalls the thin fingers of desert trees. The photographs are at once playful and beautiful, peaceful and provocative. This photo essay includes work from Aguilar’s series, plus a similar work by California photographer Judy Dater, which influenced Aguilar.

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Launeau, Patrick, Christophe Sotin und Jacques Girardeau. „Cartography of the Ronda peridotite (Spain) by hyperspectral remote sensing“. Bulletin de la Société Géologique de France 173, Nr. 6 (01.11.2002): 491–508. http://dx.doi.org/10.2113/173.6.491.

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Abstract The Ronda Peridotite, south of Andalusia (Spain), was imaged by AVIRIS in 1991 and partially sampled by us in the field with a GER 3700 spectrometer in 1997 in order to get experience in processing hyperpectral images of planetary surfaces with probes such as ISM Phobos (1989), OMEGA Mars Express (2003) and VIMS Cassini (2004). The high spectral resolution of the images (224 channels from 400 to 2455 nm) is necessary to conduct geological analysis with remote petrological determinations of rock types. On Earth, it is also necessary to determine species of vegetation because of their strong influence in mapping lithology, even in dry areas like the Ronda peridotite. The Ronda AVIRIS image was first processed to infer geological features using photo-interpretation of colour composite images extracted from 150 useful channels compared to geological maps and checked on the field during the campaign of July 97. This allows us to distinguish easily the peridotite massif from its surrounding rocks and its own serpentine zoning. Since this work followed the work of Chabrillat et al. [2000] we chose to explore the AVIRIS data with other techniques. We chose to remove the contribution of the atmosphere with spectra collected in the field on a white target at various altitudes and to remove the main vegetation with spectra of the most characteristic vegetation of the peridotite. In both cases we first estimated the amount of atmosphere and vegetation with band ratios and remove them with two similar empiric corrections of the reflectance. From the spectroscopy data, after removal of the atmosphere and some vegetation signal, we were able to clearly distinguish the crustal rocks from the mantle ones, as well as compositional variations due to pyroxene and mostly serpentine abundance within the peridotites. Hyperspectral infrared spectrometry will provide good geological mapping of the main rocks on planetary surfaces, if images can also be calibrated with in situ field measurements which will not miss any unexpected component. However, some ambiguities remain between certain types of rock which have close mineralogical composition (e.g. harzburgite compared to lherzolite) or which have resulting spectra very similar to each other (plagioclase and lizardite in peridotites). Some other ambiguities between spectra are also introduced by techniques of analysis based on relative reflectance. By not taking into account absolute intensity of the reflectance, because of roughness and topographic shading effects, small mineral variations are not always visible.

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Hoshino, Masato, Kentaro Uesugi und Naoto Yagi. „Development of an X-ray imaging detector for high-energy X-ray microtomography“. Journal of Synchrotron Radiation 27, Nr. 4 (19.05.2020): 934–40. http://dx.doi.org/10.1107/s1600577520004920.

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A dedicated X-ray imaging detector for 200 keV high-energy X-ray microtomography was developed. The novelty of the detector is a large-format camera lens employed for a wide field of view. Several scintillators were evaluated in terms of the degree of efficiency of detection for high-energy X-ray photons and the modulation transfer function. For tomographic measurement, a high-definition CMOS camera was incorporated in the detector to achieve a high spatial resolution while keeping the field of view wide. Rocks with fossil inclusions were imaged to demonstrate the applicability of the detector to high-energy X-ray microtomography.

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Bertaina, Mario, Toshikazu Ebisuzaki, Piero Galeotti und Fumiyoshi Kajino. „THE JEM-EUSO MISSION“. Acta Polytechnica 53, A (18.12.2013): 811–13. http://dx.doi.org/10.14311/ap.2013.53.0811.

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The JEM-EUSO mission explores the origin of the extreme energy cosmic rays (EECRs) above 50EeV and explores the limits of the fundamental physics, through the observations of their arrival directions and energies. It is designed to open a new particle astronomy channel. This superwide-field (60 degrees) telescope with a diameter of about 2.5m looks down from space onto the night sky to detect near UV photons (330 ÷ 400nm, both fluorescent and Cherenkov photons) emitted from the giant air showers produced by EECRs. The arrival direction map with more than five hundred events will tell us the origin of the EECRs and allow us to identify the nearest EECR sources with known astronomical objects. It will allow them to be examined in other astronomical channels. This is likely to lead to an nderstanding of the acceleration mechanisms perhaps producing discoveries in astrophysics and/or fundamental physics. The comparison of the energy spectra among the spatially resolved individual sources will help to clarify the acceleration/emission mechanism, and also finally confirm the Greisen–Zatsepin–Kuz’min process for the validation of Lorentz invariance up to γ ~ 1011. Neutral components (neutrinos and gamma rays) can also be detected as well, if their fluxes are high enough. The JEM-EUSO mission is planned to be launched by a H2B rocket about 2017 and transferred to ISS by H2 Transfer Vehicle (HTV). It will be attached to the Exposed Facility external experiment platform of “KIBO”.

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Pradhananga, Dhiraj, John W. Pomeroy, Caroline Aubry-Wake, D. Scott Munro, Joseph Shea, Michael N. Demuth, Nammy Hang Kirat, Brian Menounos und Kriti Mukherjee. „Hydrometeorological, glaciological and geospatial research data from the Peyto Glacier Research Basin in the Canadian Rockies“. Earth System Science Data 13, Nr. 6 (16.06.2021): 2875–94. http://dx.doi.org/10.5194/essd-13-2875-2021.

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Abstract. This paper presents hydrometeorological, glaciological and geospatial data from the Peyto Glacier Research Basin (PGRB) in the Canadian Rockies. Peyto Glacier has been of interest to glaciological and hydrological researchers since the 1960s, when it was chosen as one of five glacier basins in Canada for the study of mass and water balance during the International Hydrological Decade (IHD, 1965–1974). Intensive studies of the glacier and observations of the glacier mass balance continued after the IHD, when the initial seasonal meteorological stations were discontinued, then restarted as continuous stations in the late 1980s. The corresponding hydrometric observations were discontinued in 1977 and restarted in 2013. Datasets presented in this paper include high-resolution, co-registered digital elevation models (DEMs) derived from original air photos and lidar surveys; hourly off-glacier meteorological data recorded from 1987 to the present; precipitation data from the nearby Bow Summit weather station; and long-term hydrological and glaciological model forcing datasets derived from bias-corrected reanalysis products. These data are crucial for studying climate change and variability in the basin and understanding the hydrological responses of the basin to both glacier and climate change. The comprehensive dataset for the PGRB is a valuable and exceptionally long-standing testament to the impacts of climate change on the cryosphere in the high-mountain environment. The dataset is publicly available from Federated Research Data Repository at https://doi.org/10.20383/101.0259 (Pradhananga et al., 2020).

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Bénard, Antoine, Sabine Palle, Luc Serge Doucet und Dmitri A. Ionov. „Three-Dimensional Imaging of Sulfides in Silicate Rocks at Submicron Resolution with Multiphoton Microscopy“. Microscopy and Microanalysis 17, Nr. 6 (18.11.2011): 937–43. http://dx.doi.org/10.1017/s1431927611011883.

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AbstractWe report the first application of multiphoton microscopy (MPM) to generate three-dimensional (3D) images of natural minerals (micron-sized sulfides) in thick (∼120 μm) rock sections. First, reflection mode (RM) using confocal laser scanning microscopy (CLSM), combined with differential interference contrast (DIC), was tested on polished sections. Second, two-photon fluorescence (TPF) and second harmonic signal (SHG) images were generated using a femtosecond-laser on the same rock section without impregnation by a fluorescent dye. CSLM results show that the silicate matrix is revealed with DIC and RM, while sulfides can be imaged in 3D at low resolution by RM. Sulfides yield strong autofluorescence from 392 to 715 nm with TPF, while SHG is only produced by the embedding medium. Simultaneous recording of TPF and SHG images enables efficient discrimination between different components of silicate rocks. Image stacks obtained with MPM enable complete reconstruction of the 3D structure of a rock slice and of sulfide morphology at submicron resolution, which has not been previously reported for 3D imaging of minerals. Our work suggests that MPM is a highly efficient tool for 3D studies of microstructures and morphologies of minerals in silicate rocks, which may find other applications in geosciences.

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Sinieghi, Ana Luiza Matos Lopes, Josefa Edivoneide Andrade dos Santos, Maria Auxiliadora Motta Barreto und João Paulo Sinieghi. „Construção de foguete de água na Educação Infantil: possibilidades de iniciação científica“. Revista Principia - Divulgação Científica e Tecnológica do IFPB 1, Nr. 50 (17.07.2020): 99. http://dx.doi.org/10.18265/1517-0306a2020v1n50p99-108.

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Scientific initiation research can begin to be introduced systematically from the beginning of school life, facilitating learning and arousing children’s curiosity. This paper addresses the topic of Scientific Initiation in Early Childhood Education, reporting a school experience. The main objective of the research was to arouse and encourage the interest and curiosity of children to the knowledge of physics through playful activities, seeking to provide the understanding of the physical phenomena involving water, air and pressure, enabling practical and innovative classes based on research and experimentation. The research stages were developed through a didactic sequence that focused specifically on the repercussion and demonstration of a water rocket. The research subjects were twenty five children of Level II of Early School Education, in a private school. Records were made by photos, video recording with subsequent transcription and organization in interactive episodes (IS). The data analysis indicates that there was an increase of the students’ knowledge about the theme approached, in a playful way.

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Torabi, A., M. U. Johannessen und T. S. S. Ellingsen. „Fault Core Thickness: Insights from Siliciclastic and Carbonate Rocks“. Geofluids 2019 (02.06.2019): 1–24. http://dx.doi.org/10.1155/2019/2918673.

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Fault core accommodates intense deformation in the form of slip surfaces and fault rocks such as fault gouge, cataclasite, breccia, lenses, shale smear, and diagenetic features. The complexity and variation in fault core geometry and thickness affect fluid flow both along and across the fault. In this study, we have investigated a total of 99 faults in siliciclastic and carbonate rocks. This has resulted in two large datasets that include 871 fault core thickness measurements T in siliciclastic rocks and 693 measurements in carbonates, conducted at regular intervals along fault elevations (fault height) on the outcrop or photos of the outcrop. Many of these measurements have been analyzed with respect to fault displacement measurements D in order to study the relationship between displacement and fault core thickness and to further uncover the fault growth process. We found that the fault type and geometry, displacement, type of fault rocks, lithology, and competency contrasts between faulted layers lead to significant variations in the fault core internal structure and thickness. Analysis of average values of fault core thickness-displacement data of this study and of previously published studies shows that the core thickness-displacement relationship follows an overall power law, in which its exponent and intercept change depending on the lithology of the faulted rocks. In general, small faults in carbonate and siliciclastic rocks (D≤5 m) show comparable T/D ratios, with a slightly higher ratio in carbonate rocks. The outcomes of this study contribute to the understanding of the fault core internal structure and variation in fault core thickness as a result of the interplay between fault displacement and host rock in different lithologies. These outcomes have significant implication for characterizing the sealing and conductivity potential of faulted rocks, which is relevant to different applications such as petroleum exploration and development of existing fields, hydrogeology, geothermal energy storage and extraction, and CO2 sequestration.

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Zheng, Wang, Geoffrey J. Gilleaudeau, Linda C. Kah und Ariel D. Anbar. „Mercury isotope signatures record photic zone euxinia in the Mesoproterozoic ocean“. Proceedings of the National Academy of Sciences 115, Nr. 42 (01.10.2018): 10594–99. http://dx.doi.org/10.1073/pnas.1721733115.

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Photic zone euxinia (PZE) is a condition where anoxic, H2S-rich waters occur in the photic zone (PZ). PZE has been invoked as an impediment to the evolution of complex life on early Earth and as a kill mechanism for Phanerozoic mass extinctions. Here, we investigate the potential application of mercury (Hg) stable isotopes in marine sedimentary rocks as a proxy for PZE by measuring Hg isotope compositions in late Mesoproterozoic (∼1.1 Ga) shales that have independent evidence of PZE during discrete intervals. Strikingly, a significantly negative shift of Hg mass-independent isotope fractionation (MIF) was observed during euxinic intervals, suggesting changes in Hg sources or transformations in oceans coincident with the development of PZE. We propose that the negative shift of Hg MIF was most likely caused by (i) photoreduction of Hg(II) complexed by reduced sulfur ligands in a sulfide-rich PZ, and (ii) enhanced sequestration of atmospheric Hg(0) to the sediments by thiols and sulfide that were enriched in the surface ocean as a result of PZE. This study thus demonstrates that Hg isotope compositions in ancient marine sedimentary rocks can be a promising proxy for PZE and therefore may provide valuable insights into changes in ocean chemistry and its impact on the evolution of life.

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Lu, Anhuai, Yan Li, Hongrui Ding, Xiaoming Xu, Yanzhang Li, Guiping Ren, Jing Liang et al. „Photoelectric conversion on Earth’s surface via widespread Fe- and Mn-mineral coatings“. Proceedings of the National Academy of Sciences 116, Nr. 20 (22.04.2019): 9741–46. http://dx.doi.org/10.1073/pnas.1902473116.

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Sunlight drives photosynthesis and associated biological processes, and also influences inorganic processes that shape Earth’s climate and geochemistry. Bacterial solar-to-chemical energy conversion on this planet evolved to use an intricate intracellular process of phototrophy. However, a natural nonbiological counterpart to phototrophy has yet to be recognized. In this work, we reveal the inherent “phototrophic-like” behavior of vast expanses of natural rock/soil surfaces from deserts, red soils, and karst environments, all of which can drive photon-to-electron conversions. Using scanning electron microscopy, transmission electron microscopy, micro-Raman spectroscopy, and X-ray absorption spectroscopy, Fe and Mn (oxyhydr)oxide-rich coatings were found in rock varnishes, as were Fe (oxyhydr)oxides on red soil surfaces and minute amounts of Mn oxides on karst rock surfaces. By directly fabricating a photoelectric detection device on the thin section of a rock varnish sample, we have recorded an in situ photocurrent micromapping of the coatings, which behave as highly sensitive and stable photoelectric systems. Additional measurements of red soil and powder separated from the outermost surface of karst rocks yielded photocurrents that are also sensitive to irradiation. The prominent solar-responsive capability of the phototrophic-like rocks/soils is ascribed to the semiconducting Fe- and Mn (oxyhydr)oxide-mineral coatings. The native semiconducting Fe/Mn-rich coatings may play a role similar, in part, to photosynthetic systems and thus provide a distinctive driving force for redox (bio)geochemistry on Earth’s surfaces.

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Xian-Wen, Huang, Zhi-Shu Yao, Wang Bing-Hui, Zhou Ai-Zhao und Peng-Ming Jiang. „Soil-Rock Slope Stability Analysis under Top Loading considering the Nonuniformity of Rocks“. Advances in Civil Engineering 2020 (16.12.2020): 1–15. http://dx.doi.org/10.1155/2020/9575307.

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Soil-rock slopes are widely distributed in central or western China. With the development of transportation, many subgrades are being built on mountainsides and therefore, slope stability has to be estimated under high loadings. To obtain better estimation results, a new rock contour establishing algorithm was developed, capable of considering interlock effect between rocks. Then, computed tomography (CT) and unconfined triaxial tests with ring top loadings were conducted. Based on rock distribution characteristics (obtained by CT photos) and the appearance of shear failure surfaces in slopes under ring top loadings, four rock skeleton status and five shear failure surface developing models were introduced. Based on the developed rock contour establishing algorithm, ten groups (twelve models per group) were established and calculated by finite element method (FEM). After this, normalized ultimate loading increasing multiple N, which was the ultimate loading ratio of rock-containing slope to uniform soil slope, was introduced to evaluate the influence of rock distributions on slope stability. The value of N was increased with the increase of rock content due to rock skeleton status. The values of N in slopes with angular rocks were about three times higher than those with round rocks which was due to complex geometric shape and distribution characteristics of angular rocks. Then, considering different slope angles (50°–60°), rock contents (0%–60%), and rock shapes (round and angular), the ultimate loading increasing multiple N of soil-rock slopes under high loadings was calculated and suggested for engineering designs. Finally, based on the failure surfaces of numerical modes, three typical failure modes were developed, which could be reference for designers to deal with slopes.

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Grice, K., R. E. Summons, E. Grosjean, R. J. Twitchett, W. Dunning, S. X. Wang und M. E. Bottcher. „DEPOSITIONAL CONDITIONS OF THE NORTHERN ONSHORE PERTH BASIN (BASAL TRIASSIC)“. APPEA Journal 45, Nr. 1 (2005): 262. http://dx.doi.org/10.1071/aj04023.

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An oil-source rock correlation has been established for the northern onshore Perth Basin (Western Australia) based on unusual aromatic and polar biomarkers attributed ultimately to a green sulphur bacterial source. Several of these biomarkers have been identified throughout the entire Sapropelic Interval of a proven petroleum source rock intersected within a recently discovered marine Permian- Triassic Perth Basin borehole (Hovea–3) and several Perth Basin crude oils. Today, green sulphur bacteria live in the anaerobic zones of stratified lakes or in marine environments with restricted water circulation, where the upper sulphide limit coincides with the lower limit of oxygen. The presence of photosynthetic pigments and carotenoids of green sulphur bacteria, or their diagenetic alteration products in sediments provide unequivocal evidence for photic zone euxinic conditions in the paleowater column. Multiple lines of evidence for photic zone euxinia and euxinic depositional conditions for the Hovea–3 source rock have been obtained from biomarker analyses. Photic zone euxinia is usually associated with the widespread deposition of organic-matter-rich sediments that constitute important source rocks for petroleum deposits that are being exploited today. With the exception of the Perth Basin, such organic-matter-rich sediments are virtually absent from Upper Permian and Lower Triassic sediments globally. Several lines of evidence indicate localised surface ocean productivity may have played a key role in the deposition of a petroleum source rock at this location, although photic zone euxinia was globally more widespread during the Permian-Triassic Superanoxic Event.

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Alit Prasetyo, Bagus, Ari Purno Wahyu und Suhendri Suhendri. „Optimization Of Image Processing Techniques In Developing Of Smart Parking System“. Journal of Information Technology 3, Nr. 1 (05.03.2021): 1–4. http://dx.doi.org/10.47292/joint.v3i1.47.

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A parking system is currently a necessity and a common facility found in the campus area of buildings and shops, the management and supervision of this parking lot generally uses third party assistance both in terms of technology and facilities used. At first the parking lot system was still conventional based by using guards in front of the gate and manually recording the entry and exit of the vehicle, a more sophisticated technology was using a camera that was combined with ticketing assistance, officers would check with photos when the car entered and left and strengthened with the use parking tickets, the two technologies have been implemented in many places, the weakness of the system is that there is a need for more than one operator to record and criminal acts will be difficult to detect if a type of vehicle of the same color is stolen because the data from the photos are indistinguishable, To solve this problem, a parking system was created with the help of image processing techniques by recording different types of vehicles even though they were of the same type and color, this system worked using computer vision algorithm rocks with a combination of OCR a Algorithm and surf algorithm, these two algorithms will help record vehicle number-plates while the surf algorithm will record the unique characteristics of the vehicle object in detail so that it will not be change

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TROVÓ, MARCELO, ARTHUR DE LIMA SILVA, ALINE SAYURI TAJIMA und ALESSANDRA IKE COAN. „Taxonomic and morphological notes on a tiny new species of Paepalanthus (Eriocaulaceae) from central Brazil“. Phytotaxa 456, Nr. 2 (20.08.2020): 203–11. http://dx.doi.org/10.11646/phytotaxa.456.2.8.

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We describe and illustrate Paepalanthus campanulatus, a new species of Eriocaulaceae from the Chapada dos Veadeiros National Park (Goiás, Brazil). The species is known from a single population with many individuals growing under rocks and in small caves, sometimes upside down attached to the top of the cave. The new species is mainly distinguished by its usually tiny, unbranched stem bearing a fasciculate inflorescence composed of mostly glabrous, campanulate capitula surrounded by whitish hyaline involucral bracts. Due to its very restricted distribution, the species may be considered endangered. It is compared with Paepalanthus albidus and P. subtilis, the morphologically most similar species. We provide details on the leaf and scape anatomy of these species, as well as comments on the distribution, habitat, ecology, and morphological variation, along with line drawings and photos of the new species.

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