3,268 research outputs found
Cooling force measurements with the phase shift method at the cryogenic storage ring CSR
The electron cooler at the cryogenic storage ring CSR located at the Max Planck Institut f¨ur Kernphysik is used for ion beam phase space cooling, with the benefit of reaching a low ion energy spread relevant, e.g., for collision studies at conditions found in interstellar medium. The electron cooling quality is implied by the cooling force, which depends on various experimental parameters. In this thesis a phase-shift method for the electron cooling force measurement and electron cooling optimization is presented. It was successfully implemented and tested by recording data for four ion beam types: Xe3+, ArH+, HeH+ and Ne2+. The data was evaluated and the resulting cooling force curves were analysed for various systematic effects. Also a theoretical model to calculate the cooling force is given and the experimental results are compared with numerically calculated cooling force curves. The model was found to describe the experimental results well. Based on this work, the cooling force measurement is expected to become a routine optimization method in the CSR experiments involving electron beams
Dielectric breakdown induced by picosecond laser pulses
The damage thresholds of transparent optical materials were investigated. Single picosecond pulses at 1.06 microns, 0.53 microns and 0.35 microns were obtained from a mode locked Nd-YAG oscillator-amplifier-frequency multiplier system. The pulses were Gaussian in space and time and permitted the determination of breakdown thresholds with a reproducibility of 15%. It was shown that the breakdown thresholds are characteristic of the bulk material, which included nine alkali halides, five different laser host materials, KDP, quartz, sapphire and calcium fluoride. The extension of the damage data to the ultraviolet is significant, because some indication was obtained that two- and three-photon absorption processes begin to play a role in determining the threshold. Throughout the visible region of the spectrum the threshold is still an increasing function of frequency, indicating that avalanche ionization is the dominant factor in determining the breakdown threshold. This was confirmed by a detailed study of the damage morphology with a high resolution microscope just above the threshold. The influence of self focusing is discussed, and evidence for beam distortion below the power threshold for complete self focusing is presented, confirming the theory of Marburger
Schubert\u27s Serenade
Woman smelling bouquet of flowers; Woman wearing scarf around head and coathttps://scholarsjunction.msstate.edu/cht-sheet-music/11265/thumbnail.jp
An Assessment of Integrated Flywheel System Technology
The current state of the technology in flywheel storage systems and ancillary components, the technology in light of future requirements, and technology development needs to rectify these shortfalls were identified. Technology efforts conducted in Europe and in the United States were reviewed. Results of developments in composite material rotors, magnetic suspension systems, motor/generators and electronics, and system dynamics and control were presented. The technology issues for the various disciplines and technology enhancement scenarios are discussed. A summary of the workshop, and conclusions and recommendations are presented
An Alternive to Critical Point Drying for Preparing Meat Emulsions for Scanning Electron Microscopy
A rapid sample drying technique is described which is useful for the simultaneous preparation of large numbers of samples as an alternative to critical point drying. The cryofractured face of meat emulsions was visualized after appl ying this technique . The fine structure of 1 ipids and proteins were found to be well preser ved in comparison to other reports which used critical point dried meat emulsions. Lipid was readily discerned from the protein matrix by selective fixation of the components in duplicate samples . Stereo imaging was useful in enhancing the texture of the cryofractured surface and as an aid in differentiating the protein matrix from the fat component of meat emulsions
Mechanistic unity of the predictive mind
It is often recognized that cognitive science employs a diverse explanatory toolkit. It has also been argued that cognitive scientists should embrace this explanatory diversity rather than pursue search for some grand unificatory framework or theory. This pluralist stance dovetails with the mechanistic view of cognitive-scientific explanation. However, one recently proposed theory – based on an idea that the brain is a predictive engine – opposes the spirit of pluralism by unapologetically wearing unificatory ambitions on its sleeves. In this paper, my aim is to investigate those pretentions to elucidate what sort of unification is on offer. I challenge the idea that explanatory unification of cognitive science follows from the Free Energy Principle. I claim that if the predictive story is to provide an explanatory unification, it is rather by proposing that many distinct cognitive mechanisms fall under the same functional schema that pertains to prediction error minimization. Seen this way, the brain is not simply a predictive mechanism – it is a collection of predictive mechanisms. I also pursue a more general aim of investigating the value of unificatory power for mechanistic explanations. I argue that even though unification is not an absolute evaluative criterion for mechanistic explanations, it may play an epistemic role in evaluating the credibility of an explanation relative to its direct competitors
Effects of early castration on carcass composition, yield and quality characteristics of meat from young reindeer (Rangifer tarandus tarandus) bulls and steers
Thirty male reindeer; n=16 bulls (control treatment) and n=14 steers (castrated males) were used to evaluate the effects of early castration on carcass yield and meat quality attributes. The reindeer were castrated at 2 and 13 months of age, and then slaughtered at 2 and 3 years of age. Live weights and carcass weights were significantly highest in the 3 year old bulls and steers. Dressing percentage did not differ between the 2 and 3 year old reindeer steers castrated at 2 months; however these values were higher than for 2 year old steers castrated at 13 months. Meat ultimate pH values (measured in the striploin; LD) were significantly highest in 2 year old steers castrated at 13 months and their corresponding control group of 2 year old bulls, indicating low muscle glycogen stores at slaughter. Castration had an effect on fat content with 3 year old steers having a higher fat content than bulls. No significant differences were found in any sensory attribute when the trained panel compared the meat from 2 year old reindeer bulls and steers. Abstract in Swedish / Sammanfattning:Effekter av tidig kastrering på slaktkroppssammansättning, styckningsutbyte och köttkvalitet hos unga renarTrettio hanrenar; n=16 tjurar (kontrolldjur) och n=14 kastrater (härkar) ingick i denna studie för att utvärdera effekterna av tidig kastrering på slaktkroppssammansättning och köttkvalitetsparametrar. Renarna kastrerades vid 2 respektive 13 månaders ålder och slaktades sedan när de var antingen 2 eller 3 år gamla. Levandevikt och slaktkroppsvikt var högst för 3 år gamla tjurar och härkar. Slaktutbytet skiljde sig inte mellan 2 och 3 år gamla härkar som kastrerats vid 2 månaders ålder, men deras slaktutbyte var högre än för de 2-åriga härkarna som kastrerats vid 13 månaders ålder. Köttets pH-värde (mätt i ytterfilén) var signifikant högst hos de 2-åriga härkarna som kastrerats vid 13 månaders ålder och deras tillhörande kontrollgrupp av 2-åriga tjurar, vilket tydde på låga nivåer av muskelglykogen vid slakt. Kastrering hade en signifikant effekt på fettinnehållet i slaktkropparna hos de 3-åriga renarna, med de högsta fetthalterna hos härkarna. Inga skillnader i ätkvalitet rapporterades när kött från 2-åriga rentjurar och härkar jämfördes
Classification and modelling of urban micro-climates using multisensoral and multitemporal remote sensing data
Remote sensing has widely been used in urban climatology since it has the advantage of a simultaneous synoptic view of the full
urban surface. Methods include the analysis of surface temperature patterns, spatial (biophysical) indicators for urban heat island
modelling, and flux measurements. Another approach is the automated classification of urban morphologies or structural types.
In this study it was tested, whether Local Climate Zones (a new typology of thermally 'rather' homogenous urban morphologies) can
be automatically classified from multisensor and multitemporal earth observation data. Therefore, a large number of parameters
were derived from different datasets, including multitemporal Landsat data and morphological profiles as well as windowed
multiband signatures from an airborne IFSAR-DHM.
The results for Hamburg, Germany, show that different datasets have high potential for the differentiation of urban morphologies.
Multitemporal thermal data performed very well with up to 96.3 % overall classification accuracy with a neuronal network
classifier. The multispectral data reached 95.1 % and the morphological profiles 83.2 %.The multisensor feature sets reached up to
97.4 % with 100 selected features, but also small multisensoral feature sets reached good results. This shows that microclimatic
meaningful urban structures can be classified from different remote sensing datasets.
Further, the potential of the parameters for spatiotemporal modelling of the mean urban heat island was tested. Therefore, a
comprehensive mobile measurement campaign with GPS loggers and temperature sensors on public buses was conducted in order to
gain in situ data in high spatial and temporal resolution
Long-Term Potentiation: One Kind or Many?
Do neurobiologists aim to discover natural kinds? I address this question in this chapter via a critical analysis of classification practices operative across the 43-year history of research on long-term potentiation (LTP). I argue that this 43-year history supports the idea that the structure of scientific practice surrounding LTP research has remained an obstacle to the discovery of natural kinds
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