TY - JOUR A1 - Witke, Klaus A1 - Brzezinka, Klaus-Werner A1 - Lamprecht, I. T1 - Is the indigo molecule pertubed in planarity by matrices? JF - Journal of molecular structure N2 - Raman spectra of pure synthetic indigo and of Maya blue of a Mexican clay sculpture are compared. The Raman spectrum of Maya blue shows extra bands assigned to vibrational modes of Bu symmetry as well as an increasing intensity of some other bands. The partial removal of the mutual exclusion rule for the centrosymmetric indigo molecule is supposed to indicate a loss of its planarity due to strong adsorption at the palygorscite matrix. KW - Indigo KW - Maya blue KW - Raman spectroscopy PY - 2003 DO - https://doi.org/10.1016/S0022-2860(03)00511-8 SN - 0022-2860 SN - 1872-8014 SN - 0377-046X VL - 661-662 SP - 235 EP - 238 PB - Elsevier CY - Amsterdam AN - OPUS4-2812 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lamprecht, I. A1 - Maierhofer, Christiane A1 - Röllig, Mathias T1 - Infrared Thermography and Thermometry of Phototropic Plants JF - Journal of thermal analysis and calorimetry N2 - Thermal investigations using infrared (IR) thermometry and false colour thermography were carried out on flowering plants in the Botanical Garden of Berlin and in a private garden. Special interest went to phototropic plants that orient their blossoms towards a light source (mainly the sun) and within this group to solar trackers (heliotropism) that follow the path of the sun during the day. Best known among the latter is the sunflower. Bowl shaped flowers comparable to satellite disks focus the solar radiation effectively on their centre, resulting in a warming of the female organs at that point. Temperature differences above ambient can be as high as 10.7 K with a mean value of 6.0 K. Pollinating insects were often observed sun-basking in the bowls or on the flower disks attracted by energetic rewards in form of nectar and heat. KW - Insects KW - IR thermography KW - IR thermometry KW - Phototropism KW - Plants PY - 2007 DO - https://doi.org/10.1007/s10973-006-7806-9 SN - 1388-6150 SN - 1418-2874 SN - 0368-4466 SN - 1572-8943 VL - 87 IS - 1 SP - 49 EP - 54 PB - Kluwer Academic Publ. CY - Dordrecht AN - OPUS4-16096 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lamprecht, I. A1 - Maierhofer, Christiane A1 - Röllig, Mathias T1 - A thermographic promenade through the Berlin Botanic Garden JF - Thermochimica Acta N2 - False colour infrared (IR) thermography was performed on a sunny summer day in the Berlin Botanic Garden. The main interest focused on blossoms of different size, colours and shapes: disk-, bowl- and funnel-like anatomy demonstrating various modes of light absorption and heating-up during the day. Some of the flowers were phototropic or even solar tracking. Blossom temperatures ranged from 18.0 to 33.3 °C (mean 26.3 ± 2.5 °C, S.D., n = 37) at 21 °C air temperature. Several thermograms showed honey- and bumblebees also. In some cases the results are compared with those of a contact-free IR thermometry. One winter- and one late-spring-flowering plant are included in the overview. KW - Infrared KW - Insects KW - Plants KW - Thermography KW - Thermometry PY - 2006 DO - https://doi.org/10.1016/j.tca.2006.02.039 SN - 0040-6031 SN - 1872-762X VL - 446 IS - 1-2 SP - 4 EP - 10 PB - Elsevier CY - Amsterdam AN - OPUS4-14433 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wiedemann, H. G. A1 - Brzezinka, Klaus-Werner A1 - Witke, Klaus A1 - Lamprecht, I. T1 - Thermal and Raman-spectroscopic analysis of Maya Blue carrying artefacts, especially fragment IV of the Codex Huamantla JF - Thermochimica Acta N2 - Maya Blue, a pigment composed of very low concentrations of natural indigo and the clay mineral palygorskite, is one of the most brilliant blue dyes, intensively used for more than 2000 years in Mesoamerica. It is extremely stable against environmental attacks and was applied by the Indians for inside and outside mural paintings, ceramics, textiles and for colouring their famous codices. In the present paper it was studied as a powder (compared with modern synthetic indigo) and as colour on tissues, a Maya clay head, and fragment IV of the famous Codex Huamantla. Investigations using Raman spectroscopy in the visible and near-infrared range showed a high degree of correspondence among all Maya Blue-carrying samples and a good agreement with synthetic indigo. Additional spectral lines may be explained by a transformation of the planar indigo molecule when binding to the palygorskite lattice. Thermal investigations of the original “amatl” paper of the codex and of recent paper from fig-trees showed a high similarity and thus proved that this tree was chosen for paper making by Mayas, Aztecs and other Indian tribes. This was also true for the codex. KW - Art KW - Codices KW - Differential scanning calorimetry KW - Mesoamerica KW - Raman spectroscopy KW - Thermogravimetry PY - 2007 SN - 0040-6031 SN - 1872-762X VL - 456 IS - 1 SP - 56 EP - 63 PB - Elsevier CY - Amsterdam AN - OPUS4-14794 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -