Experimental Investigation of Turbulence Specifications of Turbidity Currents

The present study investigates the turbulence characteristic of turbidity current experimentally. The three-dimensional Acoustic-Doppler Velocimeter (ADV) was used to measure the instantaneous velocity and characteristics of the turbulent flow. The experiments were conducted in a three-dimensional channel for different discharge flows, concentrations, and bed slopes. Results are expressed at various distances from the inlet, for all flow rates, slopes and concentrations as the distribution of turbulence energy, Reynolds stress and the turbulent intensity. It was concluded that the maximum turbulence intensity happens in both the interface and near the wall. Also, it was observed that the turbulence intensity reaches its minimum where maximum velocity occurs

Effect of strain energy on corrosion behavior of ultrafine grained copper prepared by severe plastic deformation

Data Availability Statement The processed data needed to reproduce these findings cannot be shared at this time, as they also form part of an ongoing study, in accordance with the funder's data retention policy.Copyright 2022 The Authors. Effect of strain energy on corrosion behavior of ultrafine-grained (UFG) copper prepared by severe plastic deformation (SPD) was investigated in terms of microstructural evolution. The SPD processed material showed an ultrafine-grained (UFG) structure after grain refinement for several time processes, which will affect mechanical and corrosion behavior Homogeneity can be obtained efficiently through the pressing process commonly known as simple shear extrusion (SSE), which is one of the SPD techniques. Pure copper was processed by SSE for two, four, eight, and twelve passes. The structure of SSE treated sample was observed by laser microscope and transmission electron microscope as well as X-ray diffraction. The corrosion behavior by potentiodynamic polarization curve was observed in modified Livingstone solution, 1 M NaCl, and sulphuric solution. The structure of SSE processed sample showed that the first pass of the SSE processed sample displayed large deformation by developing the elongated grain and sub-grain structure. By increasing the SSE pass number, the grain shape became equiaxed due to excessive strain. The X-ray broadening related to ultrafine-grained (UFG) structure processed SSE on the copper sample, leading to smaller crystallite size, higher microstrain, and higher dislocation density. More homogeneous passive film was developed on the material with UFG structure appearance. However, the current density in 1 M NaCl was decreased by an increment of pass number due to the dissolution of copper metal. The UFG structure has more boundaries than coarse grain structure, and these phenomena show why Cu dissolve ability influences the current density. The grain boundary behaves as the cathodic site.Grant-in-Aid for Scientific Research on Innovative Areas “Bulk nano metals,” MEXT Japan (No 25102710) and Research and Innovation for Indonesia Research Fund Program (RIIM) No. B811/II.7.5/FR/6/2022 and B2103/III.2/HK.04.03/7/2022

Improving hydro-formability of stainless steel tubes by tube channel pressing

© Published under licence by IOP Publishing Ltd. Tube channel pressing (TCP), which is one of the severe plastic deformation (SPD) technologies to refine grain size into submicron size for tubular materials, have been applied to ferritic stainless steel tubes for one pass, in order to alleviate ridging and enhance the hydro-formability. It was found that grain-scale shear bands were introduced by one-pass TCP, and texture and microstructure was successfully modified by promoting recrystallization of deformation microstructure, which is otherwise hard-to-recrystallize, in the post-TCP annealing. Elongation to failure, strain-hardening exponent (n-value) and Lankford values of both longitudinal and circumferential directions increased in comparison to with the tube fabricated by conventional process.Japan Science and Technology Agency (JST) matching planner program

Transition of Dislocation Structures in Severe Plastic Deformation and Its Effect on Dissolution in Dislocation Etchant

© 2018 Muhammad Rifai et al. Transition of dislocation structures in ultrafine-grained copper processed by simple shear extrusion (SSE) and its effects on dissolution were manifested by simple immersion tests using a modified Livingston dislocation etchant, which attacks dislocations and grain boundaries selectively. The SSE process increased the internal strain evaluated by X-ray line broadening analysis until eight passes but decreased it with further extrusion until twelve passes. The weight loss in the immersion tests reflected the variation in the internal strain: namely, it increased until eight passes and then decreased with further extrusion to twelve passes. Taking our previous report on microstructural observation into account, it is suggested that variation in the internal strain is caused by both the variation in dislocation density and structural change of grain boundaries from equilibrium to nonequilibrium states or vice versa. Decreased dislocation density and structural change back to equilibrium state of grain boundaries in very high strain range by possibly dynamic recovery as pointed out by Dalla Torre were validated by X-ray and dissolution in the modified Livingston etchant in addition to the direct observation by TEM reported in our former report

Role of strain reversal in microstructure and texture of pure al during non-monotonic simple shear straining

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Dyestuff is one of the most widely released pollutants into the environment. Many approaches have been considered to deal with the dye removal from polluted water such as adsorption, ultrafiltration, osmosis, solvent extraction and photocatalytic degradation. The photocatalytic degradation process is one of the most beneficial, economical and environmentally friendly ways to degrade the organic pollutants from wastewater. In this study, an efficient ferrite-based photocatalyst, AgFeO2/rGO/TiO2 was successfully developed using simple deposition and reflux method. Physical, chemical and structural properties were analyzed by using XRD, FTIR Raman and PL spectroscopy. The efficiency of photocatalyst was investigated for the decolorization of methyl blue (MB) dye and activity was measured through UV-vis spectroscopy. The effect of parameters like pH, concentrations of MB dye, and loading of silver ferrite (AgFeO2) was investigated. The study depicted that the properties of TiO2 were improved due to addition of silver ferrite and reduced graphene oxide (rGO). The 2.5% AgFeO2/rGO/TiO2 exhibited the highest efficiency and completely degraded the 50 ppm of MB dye in 30 min. The parametric study revealed that dye decolorization is faster in a neutral solution than in basic and acidic medium. The higher performance of the photocatalyst was attributed to the reduced charge recombination and improved optical properties. Thus, AgFeO2/rGO/TiO2 can be a potential composite for photocatalytic dye degradation and other photocatalytic applications under UV-Visible light irradiations

On the Production of Severely Deformed Workpieces in Large Scales: A Step Towards Industrialization

© 2019, The Author(s). Improvement of the functional properties of aluminium and its alloys by grain refinement is an effective way to increase their applications. The capability of severe plastic deformation methods to produce ultrafine-grained materials has been well established. However, their industrial application is limited because of the required additional equipment and limitation of the product size. Due to the direct extrusion characteristic of the simple shear extrusion (SSE) method and consequently the minimal additional tools and expenses, SSE is a good candidate for commercialization. The aim of this research is to scale up the SSE products to facilitate their potential use in practical applications. To overcome the limitation on the length of the plunger and reduce the load of the SSE process, a design is proposed in the current research. Microstructural investigations and mechanical tests of commercial pure aluminium (AA1050) workpieces confirm the effectiveness of the proposed design on the grain refinement and its capability to reduce the processing load

Velocity independent constraints on spin-dependent DM-nucleon interactions from IceCube and PICO

[EN] Adopting the Standard Halo Model (SHM) of an isotropic Maxwellian velocity distribution for dark matter (DM) particles in the Galaxy, the most stringent current constraints on their spin-dependent scattering cross-section with nucleons come from the IceCube neutrino observatory and the PICO-60 C3F8 superheated bubble chamber experiments. The former is sensitive to high energy neutrinos from the self-annihilation of DM particles captured in the Sun, while the latter looks for nuclear recoil events from DM scattering off nucleons. Although slower DM particles are more likely to be captured by the Sun, the faster ones are more likely to be detected by PICO. Recent N-body simulations suggest significant deviations from the SHM for the smooth halo component of the DM, while observations hint at a dominant fraction of the local DM being in substructures. We use the method of Ferrer et al. (JCAP 1509: 052, 2015) to exploit the complementarity between the two approaches and derive conservative constraints on DM-nucleon scattering. Our results constrain sigma SD less than or similar to 3x10-39cm2 (6x10-38cm2) at greater than or similar to 90% C.L. for a DM particle of mass 1 TeV annihilating into tau+tau- (bb) with a local density of rho DM=0.3GeV/cm3. The constraints scale inversely with rho DM and are independent of the DM velocity distribution.Aartsen, MG.; Ackermann, M.; Adams, J.; Aguilar, JA.; Ahlers, M.; Ahrens, M.; Alispach, C.... (2020). Velocity independent constraints on spin-dependent DM-nucleon interactions from IceCube and PICO. The European Physical Journal C. 80(9):1-8. https://doi.org/10.1140/epjc/s10052-020-8069-5S18809F. Ferrer, A. Ibarra, S. Wild, JCAP 1509(09), 052 (2015). arXiv:1506.03386 [hep-ph]S. van den Bergh, Publ. Astron. Soc. Pac. 111, 657 (1999). arXiv:astro-ph/9904251G. Bertone, D. Hooper, J. Silk, Phys. Rept. 405, 279 (2005). arXiv:hep-ph/0404175A.K. Drukier, K. Freese, D.N. Spergel, Phys. Rev. D 33, 3495 (1986)M. Kuhlen, N. Weiner, J. Diemand, P. Madau, B. Moore, D. Potter, J. Stadel, M. Zemp, JCAP 1002, 030 (2010). arXiv:0912.2358 [astro-ph.GA]M. Lisanti, L.E. Strigari, J.G. Wacker, R.H. Wechsler, Phys. Rev. D 83, 023519 (2011). arXiv:1010.4300 [astro-ph.CO]Y.Y. Mao, L.E. Strigari, R.H. Wechsler, H.Y. Wu, O. Hahn, Astrophys. J. 764, 35 (2013). arXiv:1210.2721 [astro-ph.CO]L. Necib, M. Lisanti, V. Belokurov, arXiv:1807.02519 [astro-ph.GA]N.W. Evans, C.A.J. O’Hare, C. McCabe, Phys. Rev. D 99(2), 023012 (2019). arXiv:1810.11468 [astro-ph.GA]M.G. Aartsen et al. [IceCube Collaboration], Eur. Phys. J. C 77, no. 3, 146 (2017) arXiv:1612.05949 [astro-ph.HE]C. Amole et al., [PICO Collaboration]. Phys. Rev. Lett. 118(25), 251301 (2017). arXiv:1702.07666 [astro-ph.CO]M.T. Frandsen, F. Kahlhoefer, C. McCabe, S. Sarkar, K. Schmidt-Hoberg, JCAP 1201, 024 (2012). arXiv:1111.0292 [hep-ph]K. Choi, C. Rott, Y. Itow, JCAP 1405, 049 (2014). arXiv:1312.0273 [astro-ph.HE]A. Achterberg et al., [IceCube Collaboration]. Astropart. Phys. 26, 155 (2006). arXiv:astro-ph/0604450R. Abbasi et al. [IceCube Collaboration], Nucl. Instrum. Meth. A 601, 294 (2009) arXiv:0810.4930 [physics.ins-det]M.G. Aartsen et al. [IceCube Collaboration], JINST 12, no. 03, P03012 (2017) arXiv:1612.05093 [astro-ph.IM]R. Abbasi et al., [IceCube Collaboration]. Astropart. Phys. 35, 615 (2012). arXiv:1109.6096 [astro-ph.IM]G.J. Feldman, R.D. Cousins, Phys. Rev. D 57, 3873 (1998). https://doi.org/10.1103/PhysRevD.57.3873. arXiv:physics/9711021 [physics.data-an]M. Tanabashi et al. [Particle Data Group], Phys. Rev. D 98, no. 3, 030001 (2018)C. Amole et al. [PICO Collaboration], arXiv:1905.12522 [physics.ins-det]C. Amole et al. [PICO Collaboration], Phys. Rev. D 93, no. 5, 052014 (2016) arXiv:1510.07754 [hep-ex]E. Tollerud et al. [ERFA] Computational Science and Discovery, no 8, 1 (2015) https://doi.org/10.5281/zenodo.1021149J.N. Bahcall, R.K. Ulrich, Rev. Mod. Phys. 60, 297 (1988)T. Mumford et al. [SunPy Community] Computational Science and Discovery, no 8, 1 (2015) arXiv:1505.02563 [astro-ph]V. Gluscevic, M.I. Gresham, S.D. McDermott, A.H.G. Peter, K.M. Zurek, JCAP 1512(12), 057 (2015). arXiv:1506.04454 [hep-ph]A.L. Fitzpatrick, W. Haxton, E. Katz, N. Lubbers, Y. Xu, ‘, JCAP 1302, 004 (2013). https://doi.org/10.1088/1475-7516/2013/02/004. arXiv:1203.3542 [hep-ph]A. Ibarra, A. Rappelt, JCAP 1708(08), 039 (2017). arXiv:1703.09168 [hep-ph