Hasil untuk "Physics"

N. Bohr, W. Noll

Akademii︠a︡ medit︠s︡inskikh nauk Sssr

R. Jahn, F. Lyman

I. Spalding

C. Wieman, L. Hollberg

Wolfgang Baumjohann, R. Treumann

This textbook deals with the requirements of space physics. The first part starts with a description of the Earth's plasma environment, followed by a derivation of single particle motions in electromagnetic fields, with applications to the Earth's magnetosphere. Then the origin and effects of collisions and conductivities, formation of the ionosphere, magnetospheric convection and dynamics, and solar wind-magnetosphere coupling are discussed.The second part of the book presents a more theoretical foundation of plasma physics, starting from kinetic theory. Introducing moments of the distribution function permits derivation of the fluid equations, followed by an analysis of fluid boundaries, with the Earth's magnetopause and bow shock as examples. Finally, fluid and kinetic theory are applied to derive the relevant wave modes in a plasma.A representative selection of the many space plasma instabilities and relevant aspects of nonlinear theory is given in a companion textbook, Advanced Space Plasma Physics, by the same authors.

M. Rees

J. Orenstein, A. Millis

Y. Guéguen, V. Palciauskas, R. Jeanloz

L. McDermott, E. Redish

Shivasubramanian Gopinath, Joseph Rosen, Vijayakumar Anand

Fresnel incoherent correlation holography (FINCH) is a self-interference-based incoherent digital holography method. In FINCH, light from an object point is split into two beams, modulated differently using two lenses with different focal distances, and creates a self-interference hologram. At least three phase-shifted holograms are recorded and synthesized into a complex hologram, which reconstructs the object image without twin image and bias noises. Compared with conventional imaging, FINCH exhibits a longer depth of focus (DOF) and higher lateral resolution. In this study, we propose and demonstrate a new method termed post-engineering of axial resolution in FINCH (PEAR-FINCH), which enables post-recording DOF engineering for the first time. In PEAR-FINCH, a library of FINCH holograms catalogued with unique axial characteristics, DOF, and focus location is recorded by changing the focal distance of one of the diffractive lenses. Selected holograms from this library are combined to engineer new axial characteristics not achievable in FINCH. A two-step reconstruction, involving numerical back-propagation and deconvolution with a point spread hologram, is implemented. Experiments with multiplane objects having large axial separations confirm that PEAR-FINCH achieves a substantially extended DOF compared with direct imaging and FINCH. PEAR-FINCH will be promising for applications in biomedical imaging, holography, and fluorescence microscopy.

Timothy D. Wiser

Ultralight dark matter is a hypothetical class of particle with a number of interesting theoretical and experimental properties, many of which are best understood by direct analogy with or application of undergraduate physics. We present a series of exercises and discussions which may inspire the reader to bring contemporary research on ultralight dark matter into the undergraduate classroom.

S. Ramandurai

Aida Meto

Bearing in mind the expression, “<i>The art challenges the technology, and the technology inspires the art</i>”, we say that oral surgery is changing rapidly due to the introduction of new technologies that improve the way surgical treatments are planned and performed [...]

Justyna Adamczyk

Coal sludge, a fine-grained by-product of hard coal benefit, comprises a mixture of coal particles and mineral and organic matter. Generated during sedimentation and dewatering processes in preparation plants, it is typically recovered as a semi-solid filter cake. The material has potential applications in energy production and, with appropriate processing and stabilization, could be utilized in geotechnical facilities. The strength properties defined by the internal friction angle and cohesion, as well as the deformation properties expressed by compressibility, are among the most important mechanical characteristics of soil. This article presents tests of coal sludge, for which the internal friction angle, cohesion, and oedometric primary and secondary moduli were determined. The material was prepared at its optimum moisture content and maximum dry density prior to testing. In the direct shear test, using a shear box of 6 × 6 cm, each sample was consolidated for 24 h under the applied vertical stress, under which it was subsequently sheared. The shear rate was constant at 0.01 mm/min, and the test was conducted up to 10% horizontal deformation. The vertical stresses applied ranged from 50 to 200 kPa. In the oedometer test, samples were prepared to fit the dimensions of the oedometer ring, and each subsequent load stage was applied after 24 h. The range of vertical stresses in this test was from 12.5 to 400 kPa. The results of the direct shear test (φ = 24°, c = 28 kPa) are similar to the strength parameters typically obtained for medium-cohesive soils, such as sandy silt (φ = 22°, c = 25 kPa. The results of the compressibility tests (0.89 MPa < M₀ < 6.35 MPa) correspond to values characteristic of organic soils, for example, organic silts (0.5 MPa < M₀ < 5 MPa). Moreover, analysis of the consolidation curves showed that up to a vertical stress of 100 kPa, coal sludge does not exhibit rheological behavior. The obtained results indicate that coal sludge, when compacted up to its optimum moisture content and to an adequate dry density, can be effectively utilized for geotechnical applications, such as the construction of isolation barriers, as a component of geotechnical mixtures, or as a sealing material for the reclamation of post-mining areas.

Krina Parmar, Pauline Dufour, Emma Texier et al.

Abstract The nature of lead zirconate, the historical antiferroelectric material, has recently been challenged. In PbZrO3 epitaxial films, thickness reduction engenders competition among antiferroelectric, ferrielectric and ferroelectric phases. All studies so far on PbZrO3 films have utilized commercially-available oxide single crystals with large compressive lattice mismatch, causing the films to undergo strain relaxation. First-principles calculations have predicted that tensile strain can stabilize antiferroelectricity down to the nanometre scale. Here we use tensile strain imposed by artificial substrates of LaLuO3 to stabilize a pure antiferroelectric phase in PbZrO3. Sharp double hysteresis loops of polarization vs electric field show zero remanent polarization, and polar displacement maps reveal the characteristic up-up-down-down antipolar pattern down to 9 nanometre film thicknesses. Moreover, the electron beam can move this antipolar pattern through the nucleation and annihilation of translational boundaries. These results highlight the critical role of coherent epitaxial strain in the phase stability of PbZrO3.

Jiao Pan, Tao Chen, Antonio Plaza

Revealing the spatial-temporal evolution and interactions of ecosystem services (ESs) in mining area is critical for sustainable environmental management. The temporal and spatial characteristics and changing trends of six ESs in Yuzhong mining area from 2000 to 2020 were analyzed. Pearson correlation analysis explored and elucidated the intricate tradeoffs and synergies that manifest across diverse ecosystems. The integrated ecosystem service landscape index (IESLI) was constructed on this basis, and 8 factors (both natural and human) were selected to identify the driving forces. The findings indicated that: 1) Over the past two decades, five categories of ESs have exhibited a declining trend, with water yield experiencing the most significant reduction, reaching 38.7% . 2) Among the 15 ESs pairings, tradeoffs were predominantly negatively correlated. 3) The interaction between land use/land cover and precipitation (54.5% ) emerged as the primary driving force behind the spatial heterogeneity of ESs. 4) The IESLI showed a general downward trend, decreasing from 0.51 in 2005 to 0.44 in 2020. This study provides quantitative evidence of ecosystem degradation and the intricate interrelationships among ESs in mining landscapes, highlighting the critical role of coupled spatial models in uncovering underlying patterns and mechanisms. The findings offer a scientific foundation for ecological restoration and policy-making in mining regions.

Senka Gudić, Nikša Čatipović, Marija Ban et al.

This study investigates the efficiency of electrocoagulation (EC) in removing Tartrazine Yellow (TY) azo dye from synthetic wastewater using aluminium electrodes. The effects of current density, <i>i</i> (0.008–0.024 A cm⁻²), initial solution pH (3.0–7.0), and treatment time, <i>t</i> (10–50 min) on key process parameters, including pH, temperature (<i>T</i>), TY dye concentration (<i>c</i>) and removal efficiency (<i>R</i>), anode consumption, and sludge characterisation were studied. The experiments were conducted in a batch reactor according to the experimental plan developed in Design-Expert software, which was also used for the evaluation of the obtained results. As the EC process progresses, the removal efficiency of the TY dye increases, while the removal dynamics and the final value of <i>R</i> (ranging from about 28% to 99%) depend on the experimental conditions (<i>i</i>, initial pH, and <i>t</i>). A high <i>R</i>-value is reached faster with the application of higher current densities and lower initial pH. This is associated with a higher proportion of carbon and sulphur in the sludge (from the TY dye) after the EC process. Additionally, a mathematical model was developed to predict the experimental data. A numerical optimisation method using response surface methodology (RSM) was applied to determine the optimal operating conditions for TY dye removal. This resulted in the following conditions: pH = 3.37, <i>t</i> = 18.74 min, and <i>i</i> = 0.016 A cm⁻², achieving a removal efficiency of ≈70%.

Jason Aebischer

Kaon physics observables are highly sensitive to New Physics (NP) effects and form in combination with the Standard Model Effective Field Theory (SMEFT) a powerful tool to study physics that goes beyond the Standard Model paradigm. We review recent SMEFT analyses in the Kaon sector and point out novel directions that might be investigated in the future.