Visible and near infrared diffuse reflectance spectroscopy (VisNIR-DRS) is a method being investigated for quantifying soil properties and mapping soil profiles. Because a VisNIR-DRS system mounted in a soil penetrometer is now commercially available for scanning soil profiles in situ, methodologies for using scans to map soils and quantify soil properties are needed. The overall goal of this research is to investigate methodologies for collecting and analyzing VisNIR-DRS scans of intact soil profiles to identify soil series. Methodologies tested include scanning at variable versus uniform moistures, using individual versus averaged spectra, boosting an intact spectral library with local samples, and comparing quantitative and categorical classifications of soil series. Thirty-two soil cores from two fields, representing three soil series, were extracted and scanned every 2.5 cm from the soil surface to 1.5 m or to the depth of parent material at variable field moist conditions and at uniform moist condition. Laboratory analyses for clay, sand, and silt were performed on each horizon. Soil series were classified using partial least squares regression (PLS) and linear discriminant analysis (LDA). A Central Texas intact spectral library (n=70 intact cores) was used for PLS modeling, alone and boosted with the two fields. Because whole-field independent validation was used, relative percent difference (RPD) values were used to compare model performance. Wetting soils to uniform moisture prior to scanning improved prediction accuracy of total clay and RPD improved by 53 percent. Averaging side-by-side scans of the same soil profile improved prediction accuracy of RPD by 10 percent. When creating calibration models, boosting a library with local samples improved prediction accuracy of clay content by 80 and 34 percent for the two fields. Principal component plots provided insight on the spectral similarities between these datasets. Overall, using PLS alone performed the same as LDA at predicting soil series. Most importantly, results of this project reiterate the importance of fully-independent calibration and validation for assessing the true potential of VisNIR-DRS. Using VisNIR-DRS is an effective way for in situ characterization and classification of soil properties.

Ce manuscrit décrit l’élaboration d’un réseau dense et ordonné de nanoparticules épitaxiées sur couche mince d’oxyde (Al₂O₃) préparée sur un cristal de Ni₃Al (111). Des nanoparticules de Pd, et des nanoparticules à cœur de palladium et coquille d’or, ont été réalisées avec une distribution de taille étroite, grâce au fait que les centres de nucléation sont régulièrement espacés. La couche mince d’oxyde, puis le réseau de nanoparticules, sont étudiés par microscopie STM en fonction des paramètres d’oxydation du substrat et de dépôt de Pd, en particulier les températures d’oxydation et recuit, et le flux d’atomes de palladium. Au-delà de 1 ML de Pd et 1 ML d’or, le réseau devient progressivement désordonné.En plus de la microscopie STM, la faible distribution de taille permet d’étudier les nanoparticules par des mesures spectroscopiques d’ensemble : la spectroscopie vibrationnelle par génération de fréquence somme (SFG) est utilisée pour caractériser la distribution des sites d’adsorption en fonction de la taille et de la nature chimique des nanoparticules ; la spectroscopie de réflectance différentielle (DRS) est utilisée pour caractériser les propriétés plasmoniques. La SFG permet de discriminer les sites de facettes et d’arêtes ; ceci permet de montrer que les nanoparticules croissent rapidement en hauteur. Sur les particules cœur-coquille, la SFG permet d’observer la ségrégation d’atomes de Pd à travers la coquille d’or, les sites de Pd et d’or se distinguant par la fréquence de CO. CO s’adsorbe sélectivement sur les atomes de Pd à pression modérée (inférieure à 10-3 mbar), puis également sur les atomes d’or aux pressions élevées (1 mbar). De plus, à haute pression CO induit la ségrégation, réversible thermiquement, d’un grand nombre d’atomes de Pd.La DRS permet d’observer l’apparition d’une résonance plasmon pour une coquille plus large que 3 ML d’or. La résonance est d’autant plus intense que le cœur de Pd est petit, et la coquille épaisse. Mais ne devient vraiment intense qu’au voisinage de la coalescence des NPs.Ces expériences ouvrent la voie à des expériences plus fines, notamment pour sonder plus précisément les propriétés en fonction de la taille, ou l’adsorption de CO en présence d’oxygène. Elles ouvrent aussi la voie à l’étude ultérieure de l’adsorption de molécules organiques sur le réseau de nanoparticules. L’adsorption de molécules en pont sera recherchée. Le transfert d’électron dans le réseau hybride ainsi constitué sera étudié, des expériences pompe-sonde où des électrons seront excités dans les nanoparticules. La SFG permettra de sonder l’état transitoire des molécules sous l’effet du transfert de charge. / This manuscript describes the development of a dense and ordered network of epitaxially grown nanoparticles on an oxide thin-film (Al₂O₃) prepared on a Ni₃Al (111) crystal. Pd nanoparticles, and nanoparticles with palladium core and gold shell, were made with a narrow size distribution, thanks to the fact that the nucleation centers are regularly spaced. The thin oxide layer and then the nanoparticle network are studied by STM microscopy according to the substrate oxidation and Pd deposition parameters, in particular the oxidation and annealing temperatures, and the flow of palladium atoms. Beyond 1 ML of Pd and 1 ML of gold, the network becomes progressively disordered.In addition to STM microscopy, the small size distribution makes it possible to study the nanoparticles by means of overall spectroscopic measurements: the sum frequency generation (SFG) vibrational spectroscopy is used to characterize the distribution of the adsorption sites according to the size and chemical nature of the nanoparticles; differential reflectance spectroscopy (DRS) is used to characterize plasmonic properties. SFG discriminates between facet and edge sites, allowing to show that the nanoparticles grow rapidly in height. On core-shell particles, SFG allows to observe the segregation of Pd atoms across the gold shell, with Pd and gold sites distinguished by CO frequency. CO is selectively adsorbed on Pd atoms at moderate pressure (less than 10-3 mbar), then also on Au atoms at high pressures (1 mbar). Moreover, at high pressure CO induces the thermally reversible segregation of a large number of Pd atoms.The DRS makes it possible to observe the appearance of a plasmon resonance for a shell wider than 3 ML of gold. The resonance is more intense as the core of Pd is small, and the shell thick. But only becomes really intense in the vicinity of the coalescence of NPs.These experiments pave the way for finer experiments, in particular to probe more precisely the properties as a function of size, or the adsorption of CO in the presence of oxygen. They also open the way for the subsequent study of the adsorption of organic molecules on the nanoparticle network. The adsorption of molecules in bridge between nanoparticles will be sought. The electron transfer in the hybrid network thus formed will be studied using pump-probe experiments where electrons will be excited in the nanoparticles. SFG will probe the transient state of molecules under the effect of charge transfer.

Zugl.: Zürich, Univ., Diss., 2005 / Hergestellt on demand

Collection rates and recycling rates of plastic packaging are considerably lower than for other packaging materials in Sweden. In the context of a circular economy, higher plastic packaging recycling rates could contribute to increased resource efficiency and lowered greenhouse gas emissions. A deposit-returnsystem (DRS) for plastic packaging could be an appropriate economic policy instrument to increase recycling rates. This thesis investigates if and how the scope of the DRS in Sweden could be extended to post-consumer plastic packaging. Potential challenges for an extended DRS are identified through semi-structured qualitative research interviews and a literature review. Solutions to overcome the challenges are identified with lessons from earlier DRSs and are complemented with other possible solutions. The results show that the DRS scope could potentially be extended to small hollow bodies. This product group could be implemented gradually in existing infrastructure, is easy to grasp for consumers and its share of the plastic packaging waste is sufficiently high. The focus should be on non-food packaging to avoid hygienic issues. Higher consumer awareness concerning plastic issuesand policies, which incentivize plastic packaging recycling, were identified as important drivers for an extended DRS. / Insamlings- och återvinningsgraden av plastförpackningar är betydligt lägre i Sverige än för andra förpackningsmaterial. Genom att öka återvinningen av plastförpackningar kan högre resurseffektivitet och lägre utsläpp av växthusgaser uppnås. Ett pant-system för plastförpackningar kan således vara ett lämpligt styrmedel för att öka mängden återvunnet material. Detta examensarbete undersöker möjligheterna för ett utökat pantsystem i Sverige där plastförpackningar är inkluderade. Potentiella utmaningar för ett utökat system identifierades genom semi-strukturerade kvalitativa forskningsintervjuer och tillhörande litteraturstudie. Inspiration och lärdomar av liknande fall användes för att minska effekten av dessa i synergi med andra alternativa lösningar. Resultaten visar att användningen av ett pantsystem kan potentiellt utökas för att inkludera små ihåliga produkter. Denna produktgrupp kan implementeras med relativt små medel, inkorporeras i den befintliga infrastrukturen, förstås av konsumenter och står för en tillräckligt hög andel av avfallet för en mätbar effekt. Fokus bör vara på icke-livsmedelsförpackningar för att undvika risk för kontaminering. Ökad medvetenhet hos konsumenter rörande plastfrågor i kombination med tydligare riktlinjer och styrmedel för att motivera återvinning av plastförpackningar identifierades som viktiga drivkrafter för ett utökat pantsystem.

No description available.

Denna rapport utvärderar hur användningen av Drag Reduction System (DRS) skulle påverka accelerations-förlopp och energiförbrukningen vid konstant hastighet hos KTH Formula Student-bilen.Under åren har aerodynamikens betydelse inom racing ökat betydligt. För att anpassa och optimeraluftflödet runt fordonen använder motorsporter olika aerodynamiska komponenter. Generellt sett är lagenefter ökad lyftkraft mot marken(downforce) när de designar diverse aerodynamiska paket som visserligenförbättrar väggreppet men leder också till ökat luftmotstånd. Detta begränsar både topphastighet samtaccelerationsförmåga vilket leder till behovet av ett system som söker att motverka dessa begränsningar.DRS är ett system som oftast används inom motorsport och minskar luftmotståndet på raksträckor. Dettasystem fungerar som så att en mekanisk eller hydraulisk komponent öppnar vingelementen på bakvingen påraksträckor och därmed minskar luftmotståndet bilen upplever vilket ökar dess prestanda.Först gjordes en litteraturstudie för att identifiera vad som redan har undersökts för att således av-gränsa och få en ökad kunskap inom området. Baserat på resultaten från litteraturstudien och med hänsyntill de geometriska begränsningarna fastställdes nya anfallsvinklar för vingelementen när DRS är öppen.Därefter utfördes Computational Fluid Dynamics (CFD) simuleringar vid en hastighet på 40 km/hmed både öppen och stängd DRS för att utvärdera effekterna av de nya anfallsvinklarna. Resultaten visadeatt luftmotståndet minskade med cirka 55 %, medan lyftkraften som trycker ner bilen mot marken minskademed ungefär 25 %. Från detta beräknades accelerations- och hastighetsförlopp med max effekt från motorer-na samt körd sträcka under detta förlopp. Beräkningarna visade på ökad accelerationsprestanda redan eftermindre än 0,5 sekunder. Detta resulterade i en hastighetsskillnad redan vid cirka 50-60 km/h. Som en följdminskade den tid det tog att köra 60 meter med ungefär 15 hundradelar för öppen DRS jämfört med stängdDRS.För att utvärdera energiförbrukningen beräknades effekten, definierad som energi per sekund, somkrävs för att bibehålla hastigheten. Den sökta effekten beräknades med hjälp av hastighetsförloppet ochluftmotståndet vid varje hastighet. Resultatet blev att vid 40 km/h reducerades effektbehovet med 17 %,vid 100 km/h reducerades effektbehovet ännu mer ner till 36 % och vid 145 km/h, som är den maximalahastighet med stängd DRS enligt effektberäkningen, var reduceringen 40 %.Resultaten från denna studie indikerar på att luftmotståndet på bakvingen kan reduceras markant ge-nom att implementera DRS, som även ökar bilens hastighet, acceleration samt minskar energiförbrukningen.Vidare undersökningar rekommenderas för att etablera en helhetsbild av effekten av DRS på den verkligabanan Formula Student bilar tävlar på, i form av kurvtagning men även utvecklingen av en öppnings ochstängbar DRS. Dessutom rekommenderas vidare undersökning av hur det verkliga rullmotståndet förhållersig till luftmotståndet och lyftkraften för bilen i olika hastigheter.

No description available.

Univ., Diss.--Zürich, 2005.

Diffuse reflectance spectroscopy (DRS) is a rapid proximal-sensing method that is being used more and more in laboratory settings to measure soil properties. Diffuse reflectance spectroscopy research that has been completed in laboratories shows promising results, but very little has been reported on how DRS will work in a field setting on soils scanned in situ. Seventy-two soil cores were obtained from six fields in Erath and Comanche County, Texas. Each soil core was scanned with a visible near-infrared (VNIR) spectrometer with a spectral range of 350-2500 nm in four different combinations of moisture content and pre-treatment: field-moist in situ, air-dried in situ, field-moist smeared in situ, and air-dried ground. Water potential was measured for the field-moist in situ scans. The VNIR spectra were used to predict total and fine clay content, water potential, organic C, and inorganic C of the soil using partial least squares (PLS) regression. The PLS model was validated with data 30% of the original soil cores that were randomly selected and not used in the calibration model. The root mean squared deviation (RMSD) of the air-dry ground samples were within the in situ RMSD and comparable to literature values for each soil property. The validation data set had a total clay content root mean squared deviation (RMSD) of 61 g kg-1 and 41 g kg-1 for the field-moist and air-dried in situ cores, respectively. The organic C validation data set had a RMSD of 5.8 g kg-1 and 4.6 g kg-1 for the field-moist and air-dried in situ cores, respectively. The RMSD values for inorganic C were 10.1 g kg-1 and 8.3 g kg-1 for the field moist and air-dried in situ scans, respectively. Smearing the samples increased the uncertainty of the predictions for clay content, organic C, and inorganic C. Water potential did not improve model predictions, nor did it correlate with the VNIR spectra; r2-values were below 0.31. These results show that DRS is an acceptable technique to measure selected soil properties in-situ at varying water contents and from different parent materials.

Diffuse reflectance spectroscopy (DRS) is a rapid proximal-sensing method that is being used more and more in laboratory settings to measure soil properties. Diffuse reflectance spectroscopy research that has been completed in laboratories shows promising results, but very little has been reported on how DRS will work in a field setting on soils scanned in situ. Seventy-two soil cores were obtained from six fields in Erath and Comanche County, Texas. Each soil core was scanned with a visible near-infrared (VNIR) spectrometer with a spectral range of 350-2500 nm in four different combinations of moisture content and pre-treatment: field-moist in situ, air-dried in situ, field-moist smeared in situ, and air-dried ground. Water potential was measured for the field-moist in situ scans. The VNIR spectra were used to predict total and fine clay content, water potential, organic C, and inorganic C of the soil using partial least squares (PLS) regression. The PLS model was validated with data 30% of the original soil cores that were randomly selected and not used in the calibration model. The root mean squared deviation (RMSD) of the air-dry ground samples were within the in situ RMSD and comparable to literature values for each soil property. The validation data set had a total clay content root mean squared deviation (RMSD) of 61 g kg-1 and 41 g kg-1 for the field-moist and air-dried in situ cores, respectively. The organic C validation data set had a RMSD of 5.8 g kg-1 and 4.6 g kg-1 for the field-moist and air-dried in situ cores, respectively. The RMSD values for inorganic C were 10.1 g kg-1 and 8.3 g kg-1 for the field moist and air-dried in situ scans, respectively. Smearing the samples increased the uncertainty of the predictions for clay content, organic C, and inorganic C. Water potential did not improve model predictions, nor did it correlate with the VNIR spectra; r2-values were below 0.31. These results show that DRS is an acceptable technique to measure selected soil properties in-situ at varying water contents and from different parent materials.