TY - JOUR A1 - Vollmer, Michael A1 - Tammer, Robert T1 - Laboratory Experiments in Atmospheric Optics JF - In: Applied optics 37 (1998) 9, pp. 1557-1568 N2 - Old and new laboratory experiments on atmospheric optics with a focus on mirages, rainbows, and halos are presented. Some qualitative demonstrations serve primarily didactical purposes, e.g., by proving the existence of curved light rays in media with a gradient of the index of refraction, by directly visualizing the minimum-deviation curve for rainbow paths in water droplets, or by helping to elucidate the ray classes in hexagons that contribute to a specific halo. In addition, quantitative experiments allow a direct comparison of angular positions and intensities with analytical computations or Monte Carlo simulations of light scattering from small water droplets or ice hexagons. In particular, the latter can help us to understand complex halo phenomena. © 1998 Optical Society of America Y1 - 1998 U6 - https://doi.org/10.1364/AO.37.001557 SP - 1557 EP - 1568 ER - TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Pinno, Frank A1 - Vollmer, Michael T1 - Microscopic and high-speed thermal imaging: a powerful tool in physics R&D T2 - In: InfraMation proceedings Vol.10 (2009), 303-317 Y1 - 2009 SP - 303 EP - 317 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter A1 - Pinno, Frank T1 - Cheese cubes, light bulbs, soft drinks: An unusual approach to study convection, radiation and size dependent heating and cooling T2 - In: InfraMation proceedings Vol. 9 (2008), p. 477-492 Y1 - 2008 SP - 477 EP - 492 ER - TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Pinno, Frank A1 - Vollmer, Michael T1 - Night sky radiant cooling – influence on outdoor thermal imaging analysis T2 - In: InfraMation proceedings Vol. 9 (2008), 279-295 Y1 - 2008 SP - 279 EP - 295 ER - TY - CHAP A1 - Pinno, Frank A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael T1 - Thermography of window panes – problems, possibilities and troubleshooting T2 - In: InfraMation proceedings Vol. 9 (2008), 355-362 Y1 - 2008 SP - 355 EP - 362 ER - TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Pinno, Frank A1 - Vollmer, Michael T1 - Influence of wind effects on thermal imaging results – Is the wind chill effect relevant ? T2 - In: InfraMation proceedings Vol. 8 (2007), 21-31 Y1 - 2007 SP - 21 EP - 31 ER - TY - JOUR A1 - Vollmer, Michael T1 - Effects of absorbing particles on coronas and glories JF - In: Applied optics 44 (2005) 27, 5658-5666 N2 - Light scattering from small particles changes if the particles are absorbing. Whereas the effect is small for coronas and Bishop's ring, glories show pronounced attenuation with increasing absorption. Results indicate suitable wavelength regions for studies of glory scattering from cloud tops. The behavior of core-shell particles could have applications for studying the atmosphere of Venus; in addition it provides more insight into the simple ray-path model of the glory. © 2005 Optical Society of America Y1 - 2005 U6 - https://doi.org/10.1364/AO.44.005658 SP - 5658 EP - 5666 ER - TY - CHAP A1 - Christmann, S. A1 - Vollmer, Michael T1 - Jahrgangsübergreifendes Projekt zum Wetter für die Grundschule T2 - In: Didaktik der Physik : Beiträge zur Frühjahrstagung Düsseldorf 2004 ; CD zur Frühjahrstagung des Fachverbandes Didaktik der Physik in der Deutschen Physikalischen Gesellschaft / V. Nordmeier ... (Hrsg.). - Berlin : Lehmanns Media, 2004. - 1 CD-ROM. - ISBN 3-86541-066-9 Y1 - 2004 ER - TY - JOUR A1 - Gedzelman, Stanley David A1 - Vollmer, Michael T1 - Crepuscular rays: laboratory experiments and simulations JF - In: Applied Optics Vol. 50 (2011) 28, pp. F142-F151 N2 - Model simulations of laboratory-generated and natural crepuscular rays are presented. Rays are created in the laboratory with parallel light beams that pass through artificial fogs and milk–water solutions. Light scattered by 90° in a dilute mixture of whole milk first increases in intensity with distance from the source to a maximum as a result of multiple scattering by mainly small angles before decreasing exponentially due to extinction as distance continues to increase. Crepuscular rays are simulated for three cloud configurations. In case 1, the Sun at the zenith is blocked by a cloud with an overhanging anvil. The rays appear white against blue sky and are brightest when atmospheric turbidity, β≈11 . Shading by the anvil separates maximum brightness from apparent cloud edge. In case 2, a ray passes through a rectangular gap in a cloud layer. The ray is faint blue in a molecular atmosphere but turns pale yellow as β and solar zenith angle, ϕsun , increase. At ϕsun=60° it appears most striking when the cloud is optically thick, β≈5 , and the beam width Δx≈1000 m . In these cases, increasing aerosol radius, raer , to about 1000 nm brightens, narrows, and shortens rays. In case 3, the twilight Sun is shaded by a towering cloud or mountain. The shaded rays are deeper blue than the sunlit sky because the light originates higher in the atmosphere, where short waves have suffered less depletion from scattering. The long optical path taken by sunlight at twilight makes color and lighting contrasts of the rays greatest when the air is quite clean, i.e., for β−1≪1 . In all cases, the brightest rays occur when sunlight passes through an optical thickness of atmosphere, τ≈O(1) . © 2011 Optical Society of America Y1 - 2011 U6 - https://doi.org/http://dx.doi.org/10.1364/AO.50.00F142 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Rainbows, water droplets, and seeing—slow motion analysis of experiments in atmospheric optics JF - In: Applied optics Vol. 50 (2011) 28, pp. F21–F28 N2 - Many physics processes underlying phenomena in atmospheric optics happen on a rather short time scale such that neither the human eye nor video cameras are able to analyze the details. We report applications of high-speed imaging of laboratory experiments in atmospheric optics with subsequent slow motion analysis. The potential to study respective transient effects is investigated in general and for a few phenomena in detail, in particular for rainbow scattering due to single oscillating droplets during free fall, and for light propagation effects through atmospheric paths with turbulences, leading, e.g., to scintillation of stars or shimmering of mirage images. © 2011 Optical Society of America Y1 - 2011 U6 - https://doi.org/http://dx.doi.org/10.1364/AO.50.000F21 SP - F21 EP - F28 ER - TY - CHAP A1 - Vollmer, Michael A1 - Pinno, Frank A1 - Möllmann, Klaus-Peter T1 - Measurements of sun and moon with IR cameras: effects of air mass T2 - In: InfraMation proceedings. - Vol. 11 ( 2010) , 57-74 Y1 - 2010 SP - 74 ER - TY - CHAP A1 - Möllmann, Klaus-Peter A1 - Pinno, Frank A1 - Vollmer, Michael T1 - Two-color or ratio thermal imaging - potentials and limits T2 - In: InfraMation proceedings. - Vol. 11 (2010), pp.41-56 Y1 - 2010 SP - 41 EP - 56 ER - TY - CHAP A1 - Pinno, Frank A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Improved sensitivity for blower door thermography using image subtraction T2 - In: InfraMation proceedings. - Vol. 11 (2010), p. 29-40 Y1 - 2010 SP - 29 EP - 40 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - New book on IR imaging: the ultimate resource for all users T2 - In: InfraMation proceedings. - Vol. 11 (2010), pp 75-80 Y1 - 2010 SP - 75 EP - 80 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - IR imaging of gases: potential applications for CO2 cameras T2 - In: InfraMation proceedings. - Vol. 10 (2009), p.113-124 Y1 - 2009 SP - 113 EP - 124 ER - TY - CHAP A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - IR imaging of gases: quantitative analysis T2 - In: InfraMation proceedings. - Vol. 10 (2009), p. 99-112 Y1 - 2009 SP - 99 EP - 112 ER - TY - CHAP A1 - Vollmer, Michael A1 - Vujković, M. A1 - Trellu, Y. A1 - Möllmann, Klaus-Peter T1 - IR feedback loops to spotlights: thermography and contemporary dancing T2 - In: InfraMation proceedings.- Vol. 10 (2009), p. 89-97 Y1 - 2009 SP - 89 EP - 97 ER - TY - CHAP A1 - Pinno, Frank A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael T1 - Solar load and reflection effects and respective time constants in outdoor building inspections T2 - In: Inframation proceedings Vol. 10 (2009), 319-330 Y1 - 2009 SP - 319 EP - 330 ER - TY - JOUR A1 - Oertel, Christian A1 - Fandre, A. T1 - Tire Model RMOD-K 7 and Misuse Load Cases JF - In: SAE technical papers 2009-01-0582 N2 - Among load cases concerning vehicle suspension strength and durability, the misuse case is very special because of large obstacles. In this paper, an extension of the flexible belt model RMOD-K 7 concerning misuse situations is discussed. In normal rolling conditions, contact occurs between tire and road surface. To handle misuse deformations, the contact between the inner surface of the tire and the rim has to be dealt with. Results of the validation process are shown, leading to normal forces up to 70 [kN]. The model can be used together with mbs full vehicle models. One example is the determination of the critical test velocity, which generates the maximum of suspension stresses and can be found using RMOD-K 7. Y1 - 2009 ER - TY - JOUR A1 - Oertel, Christian A1 - Wei, Yintao T1 - Tyre rolling kinematics and prediction of tyre forces and moments: part I - theory and method JF - In: Vehicle system dynamics 50 (2012) 11, 1673-1687 N2 - A new method to describe tyre rolling kinematics and how to calculate tyre forces and moments is presented. The Lagrange–Euler method is used to calculate the velocity and contact deformation of a tyre structure under large deformation. The calculation of structure deformation is based on the Lagrange method, while the Euler method is used to analyse the deformation and forces in the contact area. The method to predict tyre forces and moments is built using kinematic theory and nonlinear finite element analysis. A detailed analysis of the tyre tangential contact velocity and the relationships between contact forces, contact areas, lateral forces, and yaw and camber angles has been performed for specific tyres. Research on the parametric sensitivity of tyre lateral forces and self-aligning torque on tread stiffness and friction coefficients is carried out in the second part of this paper. Y1 - 2012 U6 - https://doi.org/10.1080/00423114.2012.694452 SP - 1673 EP - 1687 ER -