Bilinear H 2-optimal Model Order-Reduction with applications to thermal parametric systems

Magdeburg, Univ., Fak. für Mathematik, Diss., 2015

Thermal biology, activity, and population parameters of Cnemidophorus vacariensis (Squamata, Teiidae), a lizard endemic to southern Brazil

We investigated the following aspects of the biology of a population of Cnemidophorus vacariensis Feltrim & Lema, 2000 during the four seasons: thermal biology, relationship with the thermal environment, daily and seasonal activity, population structure and growth rate. Cnemidophorus vacariensis is restricted to rocky outcrops of the "campos de cima da serra" grasslands on the Araucaria Plateau, southern Brazil, and is currently listed as regionally and nationally threatened with extinction. Data were collected from October 2004 through September 2007 in the state of Rio Grande do Sul. Sampling was conducted randomly from 08:00 a.m. to 6:00 p.m. The capture-mark-recapture method was employed. The lizards were captured by hand, and their cloacal temperature, sex, snout-ventral length (SVL), mass, and the temperature of their microhabitat (substrate temperature and air temperature) were recorded. Individuals were then marked by toe-clipping and released at the site of capture. Body temperatures were obtained for 175 individuals, activity data for 96 individuals, and data on population structure and growth for 59 individuals. All data were obtained monthly, at different times of the day. Cnemidophorus vacariensis average body temperature was 23.84ºC, ranging between 9.6 and 38.2ºC. Temperatures ranged between 21 and 29ºC. The correlation between external heat sources, substrate and air were positive and significant and there was a greater correlation between lizard's temperature and the temperature of the substrate (tigmothermic species). The relatively low body temperatures of individuals are associated with the climate of their environment (altitude up to 1,400 m), with large variations in temperature throughout the day and the year, and low temperatures in winter. The average body temperature observed for C. vacariensis was low when compared with that of phylogenetically related species, suggesting that the thermal biology of this species reflects adaptations to the temperate region where it lives. The monthly rates of activity of lizards were related to monthly variations in the ambient temperatures. Our data suggest that the daily and seasonal activity of C. vacariensis result from the interaction between two factors: changes in the environment temperature and the relationship between individuals and their thermal environment. The population structure of C. vacariensis varied throughout the study period, with maximum biomass in January and maximum density in February (recruitment period). The sex ratio diverged from the expected 1:1. The growth analysis showed a negative relationship between the growth rate of individuals and the SVL, revealing that young individuals grow faster than adults, a typical pattern for short-lived species. The population studied showed a seasonal and cyclical variation associated with the reproductive cycle. The life strategy of C. vacariensis seems to include adaptations to the seasonal variations in temperature, typical of its environment.

Thermal tests on the LISA pathfinder engineering model

Report for the scientific sojourn carried out at Albert Einstein Institut in Germany, from April to July 2006.

Desensitization of thermal hyperemia in the skin is reproducible.

OBJECTIVE: Local heating increases skin blood flow SkBF (thermal hyperemia). In a previous study, we reported that a first local thermal stimulus could attenuate the hyperemic response to a second one applied later on the same skin spot, a phenomenon that we termed desensitization. However, other studies found no evidence for desensitization in similar conditions. The aim of the present work was to test whether it was related to differences in instrumentation. METHODS: Twenty-eight healthy young males were studied. Two pairs of heating chambers, one custom-made (our study) and one commercial (other groups), were affixed to forearm skin. SkBF was measured with single-point laser-Doppler flowmetry (LDF) (780nm) in one pair, and laser-Doppler imaging (LDI) (633nm) in the other. A temperature step from 34 to 41°C, was applied for 30minutes and repeated after two hours. RESULTS: During the second thermal challenge, the plateau SkBF was lower than during the first thermal and was observed with each of the four combinations of SkBF measurement techniques and heating equipment (p<0.05 for all conditions, range -9% to -16% of the initial value). CONCLUSION: Desensitization of thermal hyperemia is not specific to peculiar operating conditions.

Numerical simulation of combined heat transfer phenomena (conduction, convection, and radiation). Application to he optimisation of thermal systems

Thermal systems interchanging heat and mass by conduction, convection, radiation (solar and thermal ) occur in many engineering applications like energy storage by solar collectors, window glazing in buildings, refrigeration of plastic moulds, air handling units etc. Often these thermal systems are composed of various elements for example a building with wall, windows, rooms, etc. It would be of particular interest to have a modular thermal system which is formed by connecting different modules for the elements, flexibility to use and change models for individual elements, add or remove elements without changing the entire code. A numerical approach to handle the heat transfer and fluid flow in such systems helps in saving the full scale experiment time, cost and also aids optimisation of parameters of the system. In subsequent sections are presented a short summary of the work done until now on the orientation of the thesis in the field of numerical methods for heat transfer and fluid flow applications, the work in process and the future work.

Indirect hydrogen analysis by gas chromatography coupled to mass spectrometry (GC-MS).

Gas chromatography (GC) is an analytical tool very useful to investigate the composition of gaseous mixtures. The different gases are separated by specific columns but, if hydrogen (H2 ) is present in the sample, its detection can be performed by a thermal conductivity detector or a helium ionization detector. Indeed, coupled to GC, no other detector can perform this detection except the expensive atomic emission detector. Based on the detection and analysis of H2 isotopes by low-pressure chemical ionization mass spectrometry (MS), a new method for H2 detection by GC coupled to MS with an electron ionization ion source and a quadrupole analyser is presented. The presence of H2 in a gaseous mixture could easily be put in evidence by the monitoring of the molecular ion of the protonated carrier gas. Copyright © 2013 John Wiley & Sons, Ltd.

The thermal stability of yellow fever vaccines

The assessment of yellow fever vaccine thermostability both in lyophilized form and after reconstitution were analyzed. Two commercial yellow fever vaccines were assayed for their thermal stability. Vaccines were exposed to test temperatures in the range of 8 (graus) C to 45 (graus) C. Residual infectivity was measured by a plaque assay using Vero cells. The titre values were used in an accelerated degradation test that follows the Arrhenius equation and the minimum immunizing dose was assumed to be 10 (ao cubo) particles forming unit (pfu)/dose. Some of the most relevant results include that (i) regular culture medium show the same degradation pattern of a reconstituted 17D-204 vaccine; (ii) reconstituted YF-17D-204 showed a predictable half life of more than six days if kept at 0 (graus) C; (iii) there are differences in thermostability between different products that are probably due to both presence of stabilizers in the preparation and the modernization in the vaccine production; (iv) it is important to establish a proper correlation between the mouse infectivity test and the plaque assay since the last appears to be more simple, economical, and practical for small laboratories to assess the potency of the vaccine, and (v) the accelerated degradation test appears to be the best procedure to quantify the thermostability of biological products.

Gas emission during laparoscopic colorectal surgery using a bipolar vessel sealing device: A pilot study on four patients.

BACKGROUND: Dissection during laparoscopic surgery produces smoke containing potentially toxic substances. The aim of the present study was to analyze smoke samples produced during laparoscopic colon surgery using a bipolar vessel sealing device (LigaSuretrade mark). METHODS: Four consecutive patients undergoing left-sided colectomy were enrolled in this pilot study. Smoke was produced by the use of LigaSuretrade mark. Samples (5,5l) were evacuated from the pneumoperitoneum in a closed system into a reservoir. Analysis was performed with CO2-laser-based photoacoustic spectroscopy and confirmed by a Fourier-transform infrared spectrum. The detected spectra were compared to the available spectra of known toxins. RESULTS: Samples from four laparoscopic sigmoid resections were analyzed. No relevant differences were noted regarding patient and operation characteristics. The gas samples were stable over time proven by congruent control measurements as late as 24 h after sampling. The absorption spectra differed considerably between the patients. One broad absorption line at 100 ppm indicating H2O and several unknown molecules were detected. With a sensitivity of alpha min ca 10-5 cm-1 no known toxic substances like phenol or indole were identified. CONCLUSION: The use of a vessel sealing device during laparoscopic surgery does not produce known toxic substances in relevant quantity. Further studies are needed to identify unknown molecules and to analyze gas emission under various conditions.

Cap a l'autosuficiència energètica: barri La Plana, Sitges

En el present estudi s’ha analitzat si és possible l’autosuficiència energètica al barri projectat de La Plana de Sitges a partir de fonts renovables d’energia. S’ha realitzat un anàlisi de l’oferta potencial del barri de La Plana, format per habitatges unifamiliars i plurifamiliars, serveis i equipaments i s’ha comparat el potencial de producció energètica dels recursos renovables locals a cada subsistema i pel sistema de La Plana. Diferenciant si són una Oferta estàndard (4.000 MWh/a) seguint la Normativa d’ecoeficiència de Sitges o bé una Oferta renovable (19.000 MWh/a) segons un Ecobarri proposat en aquest projecte a partir d’energia solar fotovoltaica i tèrmica. En l’estudi de la demanda, diferenciant entre una Demanda estàndard (39.000 MWh/a), respon al total de La Plana seguint el consum d’un habitatge tipus de la mitjana catalana (ICAEN, 2002) i una Demanda eficient (20.800 MWh/a) seguint un model de baix consum projectat en un Ecobarri de Barcelona. (Vallbona, 2009). Per analitzar de forma detallada les variables d’oferta i demanda, s’han proposat quatre escenaris diferents on es valoren l’autosuficiència energètica del sistema de la Plana i aspectes ambientals d’emissions derivades de la utilització de l’energia. El primer escenari és l’estàndard i és el resultat d’analitzar conjuntament una oferta i una demanda estàndard. Al segon escenari conflueixen una Oferta Estàndard i una Demanda Eficient. En el tercer escenari coincideixen una Oferta Renovable i una Demanda Estàndard. El quart i últim escenari respon a la proposta d’Ecobarri on l’Oferta és renovable i la Demanda eficient. Tanmateix, s’ha realitzat un estudi sobre els aspectes econòmics de La Plana que s’estimen en uns beneficis per la venda de l’energia d’uns 5 milions d’euros anuals i uns costos d’instal·lació de 80 milions d’euros. Finalment s’ha constatat que és possible assolir una autosuficiència del 90% a l’escenari Ecobarri (oferta renovable - demanda eficient). Mitjançant la instal·lació de sistemes de captació solar a les cobertes, cobrint el 100% de la demanda d’ACS, i captadors solars FV, ambdues estratègies són viables i representen beneficis econòmics i una reducció d’emissions de l’ordre de 13.700 Tn CO2 equivalents anuals que suposen un estalvi del 88% respecte un escenari d’oferta i demanda estàndard.

Thermal niches are more conserved at cold than warm limits in arctic-alpine plant species

Aim Understanding the stability of realised niches is crucial for predicting the responses of species to climate change. One approach is to evaluate the niche differences of populations of the same species that occupy regions that are geographically disconnected. Here, we assess niche conservatism along thermal gradients for 26 plant species with a disjunct distribution between the Alps and the Arctic. Location European Alps and Norwegian Finnmark. Methods We collected a comprehensive dataset of 26 arctic-alpine plant occurrences in two regions. We assessed niche conservatism through a multi-species comparison and analysed species rankings at cold and warm thermal limits along two distinct gradients corresponding to (1) air temperatures at 2 meters above ground level and (2) elevation distances to the treeline (TLD) for the two regions. We assessed whether observed relationships were close to those predicted under thermal limit conservatism. Results We found a weak similarity in species ranking at the warm thermal limits. The range of warm thermal limits for the 26 species was much larger in the Alps than in Finnmark. We found a stronger similarity in species ranking and correspondence at the cold thermal limit along the gradients of 2-m temperature and TLD. Yet, along the 2-m temperature gradient, the cold thermal limits of species in the Alps were lower on average than those in Finnmark. Main conclusion We found low conservatism of the warm thermal limits but a stronger conservatism of the cold thermal limits. We suggest that biotic interactions at the warm thermal limit likely modulate species responses more strongly than at the cold limit. The differing biotic context between the two regions is likely responsible for the observed differences in realised niches.

Recurrence pattern after [(18)F]fluoroethyltyrosine-positron emission tomography-guided radiotherapy for high-grade glioma: a prospective study.

PURPOSE: To assess the failure pattern observed after (18)F fluoroethyltyrosine (FET) planning after chemo- and radiotherapy (RT) for high-grade glioma. METHODS: All patients underwent prospectively RT planning using morphological gross tumour volumes (GTVs) and biological tumour volumes (BTVs). The post-treatment recurrence tumour volumes (RTVs) of 10 patients were transferred on their CT planning. First, failure patterns were defined in terms of percentage of RTV located outside the GTV and BTV. Second, the location of the RTV with respect to the delivered dose distribution was assessed using the RTV's DVHs. Recurrences with >95% of their volume within 95% isodose line were considered as central recurrences. Finally, the relationship between survival and GTV/BTV mismatches was assessed. RESULTS: The median percentages of RTV outside the GTV and BTV were 41.8% (range, 10.5-92.4) and 62.8% (range, 34.2-81.1), respectively. The majority of recurrences (90%) were centrally located. Using a composite target volume planning formalism, the degree of GTV and BTV mismatch did not correlate with survivorship. CONCLUSIONS: The observed failure pattern after FET-PET planning and chemo-RT is primarily central. The target mismatch-survival data suggest that using FET-PET planning may counteract the possibility of BTV-related progression, which may have a detrimental effect on survival.