@article{Vollmer2021, author = {Vollmer, Michael}, title = {Gefrierende Gew{\"a}sser}, series = {Physik in unserer Zeit}, volume = {52}, journal = {Physik in unserer Zeit}, number = {1}, publisher = {Wiley-Blackwell}, doi = {10.1002/piuz.202001589}, pages = {19 -- 25}, year = {2021}, language = {de} } @article{VollmerMoellmann2020, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Fata Morgana im Wasserbecken}, series = {Physik in unserer Zeit}, volume = {51}, journal = {Physik in unserer Zeit}, number = {2}, publisher = {Wiley-Blackwell}, doi = {10.1002/piuz.202001575}, pages = {98 -- 99}, year = {2020}, language = {de} } @inproceedings{RichardsHuebnerVollmer2018, author = {Richards, A. and H{\"u}bner, M. and Vollmer, Michael}, title = {Measurements of SWIR backgrounds using the swux unit of measure}, series = {Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XXIX : 17-18 April 2018, Orlando, Florida, United States}, booktitle = {Infrared Imaging Systems: Design, Analysis, Modeling, and Testing XXIX : 17-18 April 2018, Orlando, Florida, United States}, editor = {Holst, Gerald C.}, publisher = {SPIE}, address = {Bellingham, Washington, USA}, doi = {10.1117/12.2305282}, year = {2018}, language = {en} } @article{VollmerMustard2019, author = {Vollmer, Michael and Mustard, Alexander}, title = {Blue - the color of (pure) water}, series = {Physics Education}, journal = {Physics Education}, number = {Ausgabe: 4/ Band: 54}, publisher = {IOP Publishing}, issn = {0031-9120 (print) 1361-6552 (online)}, doi = {10.1088/1361-6552/ab130a}, year = {2019}, abstract = {Water can exhibit many different colors due to a variety of physical properties. Here, we focus on some observable colors within very pure freshwater. We only treat the absorption of light due to electronic and ro-vibrational excitations and scattering due to refractive index fluctuations of the water and the respective consequences for the appearance of colors.}, language = {en} } @article{Vollmer2019, author = {Vollmer, Michael}, title = {The freezing of lakes in winter}, series = {European Journal of Physics}, journal = {European Journal of Physics}, number = {Ausgabe: 3/ Band: 40}, publisher = {IOP Publishing}, issn = {1367-2630}, doi = {10.1088/1361-6404/ab07f8}, year = {2019}, abstract = {Freezing of lakes is described using a simplified one-dimensional model, which gives ice thickness, ice growth rates, and ice surface temperature as a function of time. Model data for a specific lake with known meteorological conditions are compared to estimated ice thickness using a simple optical method. Finally, more advanced potential students projects are briefly discussed and results of a numerical solution are compared to the simplified model.}, language = {en} } @article{Vollmer2023, author = {Vollmer, Michael}, title = {Die Grenzen des Auges}, series = {Physik Journal}, journal = {Physik Journal}, number = {3}, pages = {28 -- 33}, year = {2023}, abstract = {Mithilfe geeigneter Hilfsmittel lassen sich die Wahrnehmungsgrenzen des Auges {\"u}berwinden. Menschliche Augen weisen r{\"a}umliche, zeitliche und spektrale Begrenzungen auf, welche die Wahrnehmung einschr{\"a}nken. Geeignete optische Ger{\"a}te und Kameras helfen, diese zu {\"u}berwinden und eine große Vielfalt an physikalischen Ph{\"a}nomenen f{\"u}r die Lehre zu erschließen. Die Angaben zu den Anteilen an aufgenommener Information durch die menschlichen Sinnesorgane schwanken meist zwischen etwa 81 und 87 Prozent f{\"u}r die Augen, 10 bis 11 Prozent f{\"u}r die Ohren und dem Rest f{\"u}r schmecken, riechen und tasten. Das Produktmarketing macht sich dies gezielt zunutze. Offensichtlich ist f{\"u}r alle subjektiven Wahrnehmungen unserer Umwelt das Auge sehr wichtig; in Bezug auf r{\"a}umliche und zeitliche Aufl{\"o}sung sowie spektrale Empfindlichkeit ist es jedoch eingeschr{\"a}nkt. Die dadurch entstehenden Wahrnehmungsgrenzen f{\"u}r physikalische Vorg{\"a}nge und Objekte lassen sich durch geeignete optische Ger{\"a}te mit - das Auge ersetzenden - Sensoren in Kamerasystemen {\"u}berwinden (Abb. 1). Dies erh{\"o}ht die Zahl beobachtbarer technischer und nat{\"u}rlicher Ph{\"a}nomene und den daraus gewonnenen Informationsgehalt deutlich. Da entsprechende Kameras relativ preiswert sind und sich damit viele einfache Experimente erfolgreich demonstrieren lassen, kann ein gezielter Einsatz die Lehre der Physik an Schulen und in einf{\"u}hrenden Vorlesungen an Hochschulen bereichern und den Einstieg in verwandte Gebiete wie die Infrarotastronomie vorbereiten. (...)}, language = {de} } @article{Vollmer2022, author = {Vollmer, Michael}, title = {The evolution of IR imaging: What's next?}, series = {Laser Focus World Magazine}, journal = {Laser Focus World Magazine}, publisher = {endeavor business media}, pages = {23 -- 26}, year = {2022}, abstract = {The vast majority of all human sensory inputs occur through our eyes. Light from direct sources or scattered light from objects enters our eyes and is focused onto the retina. The resulting signals are interpreted by the brain, which leads to the perception of the image of the observed objects. Although quite efficient for our daily life, many technological applications require sensor properties beyond the characteristics of our eyes. A major limitation regarding microscopic objects is spatial resolution, which is overcome by microscopes. Time resolution can be dealt with using either time-lapse or high-speed cameras. Finally, eyes only detect visible radiation within the wavelength range from about 380 nm to 780 nm. Changing the detected spectral range of electromagnetic radiation can dramatically enhance our vision. Shorter wavelengths such as x-rays are valuable tools for medical imaging, while ultraviolet (UV) imaging is used for forensics. Longer-wavelength thermal radiation used for imaging is often defined within spectral ranges, characterized by the photoelectric detector materials used and the respective atmospheric windows.}, language = {de} } @incollection{Vollmer2022, author = {Vollmer, Michael}, title = {Fundamentals of Thermal Imaging}, series = {Thermal Cameras in Science Education}, booktitle = {Thermal Cameras in Science Education}, editor = {Haglund, Jesper and Jeppsson, Fredrik and Sch{\"o}nborn, Konrad J.}, publisher = {Springer}, address = {Cham}, doi = {10.1007/978-3-030-85288-7_2}, pages = {7 -- 25}, year = {2022}, abstract = {The quantitative explanation of thermal radiation in 1900 by Max Planck started a development, which today has resulted in modern infrared technologies with thermal imaging cameras. The present work briefly describes the fundamentals of infrared imaging, based on the fact, that every object at a temperature T > 0 K emits thermal radiation. Its amount is only governed by temperature and the material quantity emissivity. Factors that define types and properties of commercial IR cameras, such as temperature range in nature and industry, the atmospheric windows for IR radiation as well as available optics and detectors are discussed. A short summary of typical specifications of IR cameras and interpretation of recorded images is given.}, language = {en} } @incollection{Vollmer2022, author = {Vollmer, Michael}, title = {Infrared Cameras as Smartphone Accessory: Qualitative Visualization or Quantitative Measurement?}, series = {Thermal Cameras in Science Education}, booktitle = {Thermal Cameras in Science Education}, editor = {Haglund, Jesper and Jeppsson, Fredrik and Sch{\"o}nborn, Konrad J.}, publisher = {Springer}, address = {Cham}, doi = {10.1007/978-3-030-85288-7_9}, pages = {129 -- 145}, year = {2022}, abstract = {Recently, infrared cameras have become available as smartphone accessories. Being less expensive than regular infrared cameras they are readily affordable and widespread use in the future is expected. Available commercial models are compared and examples for meaningful use and interpretation of respective qualitative images is given. The respective arguments also directly apply to other commonly used low-grade IR cameras with similar pixel resolution and frame rates. It is assumed that users know about the typical problems due to, e.g., thermal reflections. Rather than discussing those, focus is on the danger of wrong interpretations, in particular with regard to the low frame rate, the often implemented image processing within the cameras, the imposed restrictions on necessary input parameters, and the extremely limited spatial resolution and respective errors in potential quantitative analyses.}, language = {en} } @incollection{Vollmer2022, author = {Vollmer, Michael}, title = {Physics of the Electromagnetic Spectrum}, series = {Electromagnetic Technologies in Food Science}, booktitle = {Electromagnetic Technologies in Food Science}, editor = {G{\´o}mez-L{\´o}pez, Vicente M. and Bhat, Rajeev}, publisher = {Wiley}, address = {Chichester, UK}, doi = {10.1002/9781119759522.ch1}, pages = {1 -- 32}, year = {2022}, abstract = {Electromagnetic (EM) waves, spanning about 15 orders of magnitude of wavelength (or frequency or energy) from radio waves via microwaves, infrared radiation, visible light, ultraviolet radiation, and X-rays to the highly energetic γ-rays, are utilized in food processing. In order to explain all uses of these waves in the food industry, the chapter begins with a general discussion of properties of waves and their description with wavelength frequency, speed of propagation, and also energy transport. Using visible light as starting point, electromagnetic waves in other wavelength regimes are discussed. The interaction of EM radiation with matter reveals that the wave description alone is insufficient to explain all observed phenomena. Understanding the attenuation of EM radiation in matter requires knowledge of the particle properties of electromagnetic waves, most easily summarized by the concept of photons which carry energy as well as momentum. This wave-particle duality does apply not only to EM waves, i.e. photons, but also to the particles which build up matter, in particular electrons, which also need to be described as waves. This leads to respective quantum mechanical explanations of the microscopic structure of matter in the form of atoms, molecules, and nuclei. Knowledge of their structure is a prerequisite to understand, first, the generation of EM radiation and, second, also its interaction with matter. As a result, it will become obvious that there are mostly three different usages of EM radiation in the food industry: preserving, characterizing, and heating.}, language = {en} }