The microgravity environment of the D1 mission

Some characteristic features and results of D1 microgravity measurements are discussed as performed in the Material Science Double Rack (MSDR) and the Materials Science Double Rack for Experiment Modules and Apparatus (MEDEA). Starting with a brief review of the main potential disturbances, the payload aspects of interest to the analysis and the accelerometer measuring systems are described. The microgravity data are analyzed with respect to selected mission events such as thruster firings for attitude control, operations of Spacelab experiment facilities, vestibular experiments and crew activities. The origins are divided into orbit, vehicle, and experiment induced perturbations. It has been found that the microgravity-environment is dictated mainly by payload-induced perturbations. To reduce the microgravity-level, the design of some experiment facilities has to be improved by minimizing the number of moving parts, decoupling of disturbing units from experiment facilities, by taking damping measures, etc. In addition, strongly disturbing experiments and very sensitive investigations should be performed in separate mission phases

Stratified dispersive model for material characterization using terahertz time-domain spectroscopy

We propose a novel THz material analysis approach which provides highly accurate material parameters and can be used for industrial quality control. The method treats the inspected material within its environment locally as a stratified system and describes the light-matter interaction of each layer in a realistic way. The approach is illustrated in the time-domain and frequency-domain for two potential fields of implementation of THz technology: quality control of (coated) paper sheets and car paint multilayers, both measured in humid air.Comment: 4 pages, 4 figure

Winter CO2 fluxes in a sub-alpine grassland in relation to snow cover, radiation and temperature

Carbon dioxide (CO2) emissions were measured over a period of 3 years at the sub-alpine Swiss CARBOMONT site Rigi Seebodenalp. Here we show, that winter respiration contributes larger than expected to the annual CO2 budget at this high altitude, rich in belowground organic carbon grassland (7-15% C by mass). Furthermore the contribution of winter emissions to the annual CO2 budget is highly dependent on the definition of "winter” itself. Cumulative winter respiration determined over a 6 month period from 15th of October until 15th of April contributed 23.3±2.4 and 6.0±0.3% to the annual respiration during the years under observation, respectively. The insulation effect of snow and a lowering of the freezing point caused by high concentrations of soil organic solutes prevented the soil from freezing. These conditions favored higher soil temperatures resulting in relatively high respiratory losses. The duration of snow cover and micrometeorological conditions determining the photosynthetic activity of the vegetation during snow-free periods influenced the size and the variability of the winter CO2 fluxes. Seasonal values are strongly influenced by the days at the end and the beginning of the defined winter period, caused by large variations in length of periods with air temperatures below freezing. Losses of CO2 from the snow-covered soil were highest in winter 2003/2004. These high losses were partially explained by higher temperatures in the topsoil, caused by higher air temperatures just before snowfall. Thus, losses are not a consequence of higher soil temperatures registered during the summer heat wave 2003. However, water stress in summer 2003 might have caused an increment in dead organic matter in the soil providing additional substrate for microbial respiration in the following winter. Although considerable day-to-day fluctuations in snow effluxes were recorded, no conclusive and generally valid relationship could be found between CO2 losses from the snow pack and snow depth, rate of snow melt, wind speed or air pressure. This suggests that time lags and hysteresis effects may be more important for understanding winter respiration than concurrent environmental conditions in most ecosystems of comparable typ

Taylor-Couette turbulence at radius ratio η=0.5\eta=0.5: scaling, flow structures and plumes

Using high-resolution particle image velocimetry we measure velocity profiles, the wind Reynolds number and characteristics of turbulent plumes in Taylor-Couette flow for a radius ratio of 0.5 and Taylor number of up to $6.2\cdot10^9$. The extracted angular velocity profiles follow a log-law more closely than the azimuthal velocity profiles due to the strong curvature of this $\eta=0.5$ setup. The scaling of the wind Reynolds number with the Taylor number agrees with the theoretically predicted 3/7-scaling for the classical turbulent regime, which is much more pronounced than for the well-explored $\eta=0.71$ case, for which the ultimate regime sets in at much lower Ta. By measuring at varying axial positions, roll structures are found for counter-rotation while no clear coherent structures are seen for pure inner cylinder rotation. In addition, turbulent plumes coming from the inner and outer cylinder are investigated. For pure inner cylinder rotation, the plumes in the radial velocity move away from the inner cylinder, while the plumes in the azimuthal velocity mainly move away from the outer cylinder. For counter-rotation, the mean radial flow in the roll structures strongly affects the direction and intensity of the turbulent plumes. Furthermore, it is experimentally confirmed that in regions where plumes are emitted, boundary layer profiles with a logarithmic signature are created

Spatiotemporal Visualization of THz Near-Fields in Metamaterial Arrays

We present an experimental approach to record the spatiotemporal electric field distribution of coherent broadband THz pulses propagating through planar metamaterial arrays. The electric field can be measured with sub-wavelength precision within a volume that is several wavelengths in size, thus, having the potential to map the near-field to far-field transition of the resonant structures constituting the metamaterial. To demonstrate the potential we present measurements of THz pulses propagating through a planar array of double split-ring resonators and their inverse analogue

Desmoplastic Fibroma: a benign neoplasm mimicking a malignancy

A four-year-old African male patient presented to our clinic with a two-month history of a fi rm, warm lesion involving the right side of his face. The lesion presented as a bleeding papillary mass in the 85/46 region that extended to the floor of the mouth, causing displacement of the tongue (Figure 1A-B). Upon cone-beam computed tomography (CBCT) examination, an expansile homogenous intermediate density lesion was noted with complete destruction of the bucco-lingual cortical bone. Discernible extensions were identified in the anteroposterior plane from the region of the 84 to the posterior mandible involving the right corpus, developing 46, angle and ramus but spared the condyle and coronoid processes. The lesion extended inferiorly below the epiglottis and showed a reduction of the hypopharynx. Marked bucco-lingual expansion with soft tissue swelling was noted (Figure 2A-D). An incisional biopsy was performed under general anaesthesia, and histological examination rendered a diagnosis of desmoplastic fi broma (DF)

MAXILLOFACIAL RADIOLOGY Nevoid Basal Cell Carcinoma Syndrome

An 18-year-old male patient presented at our dental clinic in 2009 for a dental assessment. A panoramic radiograph was taken to evaluate dental crowning (Figure 1). An incidental finding was noted in the right maxilla, presenting as a well-demarcated, round, unilocular, radiolucent lesion with a corticated rim extending from the right maxillary tuberosity area to distal of the 16 causing. impaction of the 18. A biopsy was taken and diagnosed as an odontogenic keratocyst (OKC) that was subsequently enucleated. In 2021 the patient returned, and another panoramic radiograph (Figure 2) and a Waters view was taken where calcification of the falx cerebri was seen (Figure 3). On the panoramic radiograph an additional mandibular lesion was visible that presented as a well-demarcated, round, unilocular, radiolucent lesion with a corticated rim extending from distal of the 46 into the missing 47, 48 area. A CBCT was then. taken to further analyse the lesions (Figure 4). A biopsy was taken in the right posterior mandible and diagnosed as an OKC. In 2023 the patient returned and a CBCT was taken. The right maxilla showed increased bone density adjacent to the enucleated lesion (Figure 5)

MAXILLOFACIAL RADIOLOGY Ectodermal dysplasia

A 9-year-old female patient presented to the clinic with a main complaint of abnormally shaped and missing teeth. Upon clinical examination, the patient had a repaired cleft lip and palate and sparse hair of her eyebrows. Intraoral and radiological examination revealed generalised enamel hypoplasia, multiple conical-shaped teeth and multiple congenitally absent teeth