Indiana University-Purdue University Indianapolis (IUPUI) / Fused deposition modeling (FDM) represents one of the most common techniques for rapid proto-typing in additive manufacturing (AM). This work applies image based thermography to monitor the FDM process in-situ. The nozzle temperature, print speed and print orientation were adjusted during the fabrication process of each specimen. Experimental and numerical analysis were performed on the fabricated specimens. The combination of the layer wise temperature profile plot and temporal plot provide insights for specimens fabricated in x, y and z-axis orientation. For the x-axis orientation build possessing 35 layers, Specimens B16 and B7 printed with nozzle temperature of 225 C and 235 C respectively, and at printing speed of 60 mm/s and 100 mm/s respectively with the former possessing the highest modulus, yield strength, and ultimate tensile strength. For the y-axis orientation build possessing 59 layers, Specimens B23, B14 and B8 printed with nozzle temperature of 215 C, 225 C and 235 C respectively, and at printing speed of 80 mm/s, 80 mm/s and 60 mm/s respectively with the former possessing the highest modulus and yield strength, while the latter the highest ultimate tensile strength. For the z-axis orientation build possessing 1256 layers, Specimens B6, B24 and B9 printed with nozzle temperature of 235 C, 235 C and 235 ➦C respectively, and at printing speed of 80 mm/s, 80 mm/s and 60 mm/s respectively with the former possessing the highest modulus and ultimate tensile strength, while B24 had the highest yield strength and B9 the lowest modulus, yield strength and ultimate tensile strength. The results show that the prints oriented in the y-axis orientation perform relatively better than prints in the x-axis and z-axis orientation.

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Thesis (PhD(Agric) (Horticulture))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: Plums with good taste, aroma and eating quality lead to repeat purchases and sustained demand. Taste includes non-volatile compounds, e.g. sugars and acids, and has been well researched to meet the consumers’ preferences. Plum aroma, however, has not enjoyed the same attention. Limited literature is available on the aroma of Japanese plums and none could be found on the effects of relatively long cold storage on the profiles. The main aim of this study is to investigate the changes in aroma compounds of Japanese plums throughout maturation and ripening and the effects of commercial cold storage regimes. Near infra-red (NIR) spectroscopy was also evaluated as a non-destructive method to determine plum quality parameters aimed at minimising sample variability. In Paper 1, NIR spectroscopy was used to develop prediction models for total soluble solid (TSS), total acidity (TA), sugar-to-acid ratio, firmness and weight in three cultivars (Pioneer, Laetitia and Angeleno) and a multi-cultivar model. Samples were collected for seven consecutive weeks and repeated over two seasons. TSS results showed excellent predictability (R2 = 0.817-0.955; RMSEP= 0.453-0.610 % Brix) but the TA models did not perform well. The sugar-to-acid ratio models had results comparable to that of TSS. Both the firmness and weight models had acceptable results. The models of ‘Pioneer’ and ‘Laetitia’ had a better predictability capacity than the ‘Angeleno’ model. Although the multi-cultivar models outperformed the single cultivar models on R2 values it had higher prediction errors. The robustness of all the TSS, TA and firmness models is high in terms of seasonality, range and cultivar. Papers 2 and 3, the main focus of the study, are concerned with the aroma profile dynamics of Japanese plums. HS-SPME was used in both papers to extract the aroma compounds followed by GC-TOFMS for separation and identification. In Paper 2, the aroma volatile compounds of three cultivars (Pioneer, Laetitia and Angeleno) were determined for a seven week period including samples from three maturity stages (immature, harvest and tree-ripe). A total of 35 compounds were identified of which ten were generic. Each cultivar had five unique compounds resulting in different aroma profiles for each of the maturity stages and distinct separation patterns using discriminant analysis. The study was extended in Paper 3 where the aroma volatile compounds of six cultivars (Pioneer, Sapphire, Laetitia, Songold, Larry Anne and Angeleno) and one plumcot (Flavor King) were determined at three functional stages (commercial harvest, tree-ripe fruit and cold stored fruit). A total of 62 compounds were identified and classified into three groups (‘unique’ (31), ‘generic’ (11) and ‘frequent’ (20)) based on their frequency of occurrence. The aroma profiles of ‘Larry Anne’ and ‘Flavor King’ are the most affected by cold storage conditions and ‘Pioneer’ appears to be the least affected. All the cultivars have significantly different aroma profiles at all three of the functional stages with ‘Sapphire’, ‘Larry Anne’ and ‘Flavor King’ showing the largest differences. ‘Flavor King’, a plumcot, presented a ripe aroma profile that was much diverged from that of the true plums. / AFRIKAANSE OPSOMMING: Pruime met ‘n goeie smaak, aroma en eetkwaliteit lei tot herhaalde verkope en volhoubare aanvraag. Smaak sluit die nie-vlugtige stowwe (suikers en sure) in en is goed nagevors om die verbruikersvoorkeure te bevredig. Pruim aroma het egter nie dieselfde aandag geniet nie. Daar is beperkte literatuur beskikbaar wat handel oor die aroma van Japanese pruime en geen kon gevind word oor die effekte van lang koelopberging op die aromaprofiele nie. Die hoof doel van hierdie studie is om die veranderinge in die aromatiese komponente van Japanese pruime te ondersoek tydens die volwassewording- en rypwordingsprosesse asook die effekte van kommersiele koelopberging. Naby infrarooi (NIR) spektroskopie is ook geevalueer as ‘n nie-destruktiewe manier om pruim kwaliteitsparameters te bepaal met die doel om monstervariasie te beperk. In Artikel 1 is NIR spektroskopie gebruik om voorspellingsmodelle vir totale oplosbare suikers (TOS), totale suur (TS), suiker-tot-suur verhouding, fermheid en gewig te bepaal in drie kultivars (Pioneer, Laetitia en Angeleno) asook ‘n multi-kultivar model. Monsters is vir sewe opeenvolgende weke versamel en herhaal oor twee seisoene. TOS resultate toon uitstekende voorspelbaarheid (R2 = 0.817-0.955; RMSEP= 0.453-0.610 % Brix) maar TS modelle het egter nie so goed gevaar nie. Die suiker-tot-suur verhoudingsmodelle se resultate was vergelykbaar met die van TOS. Beide die fermheid- en gewigsmodelle het aanvaarbare resultate opgelewer. Die modelle vir ‘Pioneer’ en ‘Laetitia’ het ‘n beter voorspelbaarheidskapasiteit getoon as die van ‘Angeleno’. Alhoewel die multi-kultivar model beter presteer het as die enkel kultivar modelle op die R2-waardes was daar meer voorspellingsfoute. Hoe robuustheid is gevind i.t.v. seisoene, datagrense en kultivar vir al die TOS, TA en fermheidsmodelle. Artikels 2 en 3, die fokuspunt van die studie, handel oor die dinamika van die aromaprofiel van Japanese pruime. HS-SPME is in beide artikels gebruik on die aromatiese verbindings te ekstraeer gevolg deur GCTOFMS vir skeiding en identifikasie. In Artikel 2 is die aromatiese stowwe van drie kultivars (Pioneer, Laetitia en Angeleno) bepaal vir sewe opeenvolgende weke en sluit monsters van drie volwassenheidsstadiums in (onvolwasse, oes en boom-rypgemaakte pruime). ‘n Totaal van 35 verbindings is geidentifiseer waarvan tien as generies beskou kan word. Elke kultivar het vyf unieke komponente gehad en het gelei tot verskillende aromaprofiele vir elk van die volwassenheidsstadiums en diverse skeidingspatrone tydens die gebruik van diskriminant analise. Die studie is uitgebrei in Artikel 3 waartydens die aromatiese vlugtige stowwe van ses kultivars (Pioneer, Sapphire, Laetitia, Songold, Larry Anne en Angeleno) en een plumcot (Flavor King) bepaal is tydens drie funksionele stadiums (oes, boom-rypgemaak en koelopgebergde pruime). ‘n Totaal van 62 verbindings is geidentifiseer en in drie groepe geklassifiseer (‘uniek’ (31), ‘generies’(11) en ‘gereeld’ (20)) gebaseer op voorkomsfrekwensie. Die aromaprofiele van ‘Larry Anne’ en ‘Flavor King’ is die meeste deur die koelopberging geaffekteer en ‘Pioneer’ die minste. Al die kultivars het kenmerkend verskil t.o.v. hul aromaprofiele in al drie die funksionele groepe en ‘Sapphire’, ‘Larry Anne’ en ‘Flavor King’ het die grootste verskille getoon. ‘Flavor King’, die plumcot, het ook ‘n ryp aromaprofiel gehad wat baie van die van die egte pruime verskil het.

Les composites thermoplastiques sont de plus en plus privilégiées dans les structures aérospatiales au vue de leur tolérance aux dommages améliorée par rapport aux résines thermodurcissables. Néanmoins, ils restent sensibles à l’impact car il produit des endommagements complexes au sein du matériau, dont le délaminage est le plus critique. La propagation de ces endommagements en compression après impact (CAI) entraîne une réduction de la tenue résiduelle. D’abord, des essais ENF ont été menés afin de déterminer la ténacité interfaciale par le biais de la méthode de la complaisance et de la technique de thermographie infrarouge. Ensuite, l’essai « Short Beam Shear » est proposé afin d’investiguer le couplage entre la fissuration matricielle et le délaminage. L’effet de la vitesse de sollicitation a été également étudié. La valeur de ténacité mesurée semble indépendante à la vitesse de sollicitation car, lors des essais réalisés, la propagation est instable. Ensuite, le comportement d’une éprouvette académique été étudié à l’aide du « Discrete Ply Model » (DPM) permettant d’enchaîner la simulation d’impact et de CAI. Ce modèle est basé sur une approche semi-discrète modélisant le délaminage et la fissuration matricielle par des éléments cohésifs, permettant de prendre en compte le couplage entre ces deux endommagements. Une vaste campagne d'essais expérimentaux d’impact et de CAI a été mise en place sur quatre empilements différents impactés à trois niveaux d’énergie. Le modèle DPM a prouvé sa capacité à prédire correctement les endommagements d’impact et de CAI. Finalement, afin de se rapprocher des conditions de structures réelles, le comportement en compression après impact d’une plaque trouée a été investigué. / High-performance thermoplastic composite have been increasingly used in aerospace applications because of their advantageous mechanical properties. Nevertheless, impact damage leads to significant reduction in structure compressive strength although damage may remain unnoticed. Delamination is the most critical damage. Short Beam Shear (SBS) test has been proposed to reproduce impact damage chronology and characterize delamination toughness. Infrared thermography is used for local measuring of fracture toughness in this unclassical test showing unstable fracture growth. Mode II fracture toughness (GIIC) values are comprised between 0.9 and 1.7 N/mm and there was no influence of the loading rate in GIIC values. Discrete Ply Model (DPM) is therefore used to model impact and compression after impact tests on laminated composite structures. Tests have been conducted in order to validate DPM capacity to capture the effects of progressive damage and failure. Impact damage and specimen’s compressive strength is well predicted by DPM. CAI damage propagation is driven by the buckling of the structure. DPM is finally employed to study impact on an industrial sample with a large diameter hole. Impact damage correlates with tests but buckling is difficult to estimate, meaning that rupture of the specimen does not correlate to tests. Nevertheless, DPM shows a good ability to predict damage in thermoplastic composite.

The synthesis, photophysical and electronic properties of a series of novel boron containing fused and ladder type donor-acceptor (D-A) oligomers and polymers are reported. The synthesis was achieved through coordination of the basic functionality of the ubiquitous benzothiadiazole acceptor unit onto a boron Lewis acid followed by an electrophilic aromatic borylation resulting in the formation of fused and ladder type structures (termed borylative fusion). The novel C,N-chelated borane structures disclosed herein are a new member of a large family of tetra-coordinate organoboron compounds that are used for the construction of highly emissive materials. Upon borylation large bathochromic shifts in the absorption and fluorescence spectra were observed, DFT and cyclic voltammetry demonstrate that this is a result of a significant reduction of the LUMO energy levels whist the HOMO energy levels remains relatively unperturbed. These large bathochromic shifts lead to materials that show far red/NIR emission in the solid state with absolute quantum yields of up to 44%. Furthermore, the frontier molecular orbital energy levels of these fused structures can be modulated through judicious selection of the exocyclic boron substituents. These novel borocycles also proved stable to a range of cross-coupling conditions which facilitated further modulation of the frontier molecular orbitals and emissive properties. Borylative fusion was also applicable to D-A conjugated polymers, this represents a facile post-polymerisation functionalisation that is an effective method of modulating the photophysical properties of D-A conjugated polymers. Solution processed OLEDs with far red/NIR electroluminescence (EL) were fabricated from these materials. These devices showed good external quantum efficiency values (EQE) for the far red/NIR region of the electromagnetic spectrum (EQE > 0.4 % for maximum EL > 700 nm).

La maladie de Parkinson est la seconde pathologie neurodégénérative la plus fréquente après la maladie d’Alzheimer. Elle se manifeste par une mort progressive et continue des neurones dopaminergiques de la voie nigro-striée, accompagnée de troubles moteurs et non moteurs lourdement handicapants. La maladie de Parkinson touche près de 6,3 millions de personnes dans le monde, avec une répartition homogène sur l’ensemble de la planète. Il existe plusieurs thérapeutiques permettant de diminuer les symptômes des malades, dont les plus efficaces sont la dopa-thérapie et la stimulation cérébrale profonde. Toutefois, à ce jour, aucune stratégie visant à protéger les neurones dopaminergiques de la dégénérescence n’a démontré son efficacité chez l’humain. En parallèle, un nombre grandissant d’études montre le potentiel cytoprotecteur d’une illumination proche infrarouge. Récemment, plusieurs études ont démontré le potentiel neuroprotecteur de cette gamme de lumière sur des modèles rongeurs de la maladie de Parkinson. L’objectif du présent travail est de confirmer ce potentiel et d’optimiser son efficacité afin de préfigurer l’essai clinique à venir. Pour ce faire, avec les modèles MPTP souris et 6-OHDA unilatéral rat, nous avons étudié la faisabilité d’une illumination intracérébrale chronique, l’influence de la longueur d’onde, de la fenêtre temporelle de traitement (pré-, post-traitement), de la quantité globale d’énergie optique apportée (continu vs discontinu, nombre de flashs lumineux, énergie d’un seul flash), de la durée d’un flash et de la puissance optique appliquée sur l’efficacité thérapeutique. Nous démontrons ici la faisabilité d’une illumination intracérébrale chronique et son potentiel neuroprotecteur. Nous montrons par ailleurs que les longueurs d’onde 670 et 810 nm protègent toutes deux les neurones dopaminergiques dans nos modèles d’étude. Nous montrons une mise en place rapide des mécanismes de protection (< 20 min), et un maintien dans le temps pendant au moins 48 heures. De plus, nous observons qu’une illumination discontinue est préférable à une illumination continue. La quantité globale d’énergie optique appliquée semble ne pas avoir de rôle significatif sur l’efficacité du traitement. En revanche, il existe un seuil bas pour la puissance optique, qui semble régie par un effet « tout-ou-rien ». L’efficacité thérapeutique est également liée à la durée d’un flash lumineux, par « un effet en cloche », Tous ces résultats sont en adéquation avec la littérature scientifique qu’ils confirment et complètent. Couplés aux travaux sur primates non humains de mon équipe d’accueil, ils serviront de base de travail à la conception du futur essai clinique. / Parkinson’s disease is the second most common neurodegenerative disease, after Alzheimer disease. It is characterized by a slow, continuous death of dopaminergic neurons in the nigrostriatal pathway, followed by severe motor and non-motor symptoms. Parkinson’s disease affects 6.3 million peoples, with a homogeneous distribution worldwide.There are several symptomatic strategies applied in clinic, such as the dopa-therapy (gold standard) and the deep brain stimulation. However, theses therapeutical approaches are not neuroprotective. Indeed, to date, there is no strategy able to effectively slow or rescue the course of the disease. Alternatively, a growing number of studies show the cytoprotective potential of a near infrared illumination. Recently, several studies showed the neuroprotective potential of these wavelengths in rodent models of Parkinson disease.The aim of this work is to confirm and optimize the efficacy of a near infrared treatment in Parkinson’s disease, as the first step for the future clinical trial.We used the MPTP mice and the 6-OHDA unilateral rat models to assess the feasibility and the effectiveness of an intracerebral chronical illumination. We also measured the influence of the wavelength, the time window (pre-, post-treatment), the global optical energy delivered (continuous vs discontinuous, number of flashs, energy of one flash), the duration of one flash and the optical power on the therapeutical efficacy.We demonstrate here the feasibility of an intracerebral chronical illumination and its neuroprotective potential. We show that the 670 and 810 nm wavelengths both protect the dopaminergic cells in the rodent models, and produce a quick activation of the protective mechanisms (< 20 min). The neuroprotective effect stays effective at least 48 hours after the illumination. Moreover, we show that a discontinuous illumination seems better than a continuous one. The global optical energy delivered has no significant influence on the efficacy. In contrast, the optical power has an everything-or-nothing effect. The therapeutic efficacy is also flash duration dependent (bell effect).All these results confirm and complete the scientific literature. Together with the work on non-human primates from my team, these results will be useful to design the future clinical trial.

We used demographic methods to address one of the main challenges facing ecological science: forecasting the effect of climate change on plant communities. Ecological forecasts will be crucial to inform long-term planning in wildland management and demographic methods are ideal to quantify changes in plant abundance. We carried out our research in the sagebrush steppe, one of the most extensive plant ecosystems of Western North America. Our research intended to inform ecological forecasts on an exotic invader, cheatgrass (Bromus tectorum). Moreover, we investigated the general question asking: to what degree competition among plants influences the outcome of ecological forecasts on the effect of climate change? We carried out two field experiments to test the hypothesis that warming will increase cheatgrass abundance in the sagebrush steppe. This hypothesis was strongly supported by both experiments. Warming increased cheatgrass abundance regardless of elevation, neighboring vegetation or cheatgrass genotype. Moreover, we found cheatgrass was hindered by snow cover. Therefore, warming increases cheatgrass growth directly by increasing temperature, and indirectly by decreasing or removing snow cover. In our last experiment, we tested whether forecasts of climate change effects on rare species can ignore competition from neighbors. This should occur because rare species should have little niche overlap with other species. The lower the niche overlap, the less competition with other species. To test this hypothesis, we used a long-term data set from an Idaho sagebrush steppe. We built population models that reproduced the dynamics of the system by simulating climate and competition. Model simulations supported our hypothesis: rare species have little niche overlap and little competitive interactions with neighbor species.

La Cathepsine K est parmi la plus efficace des collagénases de mammifère pour cliver la triple hélice de collagène de type-1. Nous avons développé une série d'azanitriles, (CKI-8 and CKI-13) inhibiteurs de cathepsine K. CKI-8 (un isomère de CKI-13) et CKI-13 ne sont pas toxiques sur les osteoblastes Saos-2 et les cellules RAW 264.7 jusqu' à une concentration de 1000 nM, tandis qu'ils ne le sont pas jusqu'à une concentration de 100 nM sur les osteoclastes. CKI-8 n'affecte pas l'activité de la phosphatase alkaline ainsi que la minéralisation induite par les Saos-2 et par les osteoblastes primaires. CKI-13 diminue de 35 % la minéralisation induite par les Saos-2 tandis qu'il n'affecte pas la minéralisation induite par les osteoblastes primaires. L'addition de CKI-13 diminue l'activité de la phosphatase alkaline d'environ 20% (Saos-2) et de 40 % (osteoblastes primaires). La résorption osseuse sur des tranches d'os d'origine bovine est diminuée avec 10 nM de CKI-13, 100 nM de CKI- 8 et 100 nM d'inhibiteur commercial E64. CKI-8 et CKI-13 diminuent la mobilité des osteoclastes. Nous avons développé un dosage d'hydrolyse de PPi par la phosphatase alkaline au moyen de l'IR, ayant l'avantage de fonctionner sur des vésicules matricielles et des cellules avec des substrats naturels à un pH physiologique. La bande de PPi localisée à 1107 cm-1 (∑= 2158 ± 211 M-1.cm-1) et celles de Pi localisées à 1076 cm-1 (∑= 1346 ± 116 M-1.cm- 1) et à 991 cm-1 (∑= 493 ± 49 M-1.cm-1) ont servis à mesurer les concentrations du substrat et du produit / Cathepsin K is among the most potent mammalian collagenase, capable of cleaving the triple helix in type-I collagen. We developed a series of azanitriles (CKI-8 and CKI-13) which are inhibitors of cathepsin K. CKI-8 (an isomer of CKI-13) and CKI-13 did not induce significant toxicity on osteoblasts Saos-2 and RAW 264.7 cells up to 1000 nM, while they were not toxic on mature osteoclasts up to 100 nM. Commercial E64 inhibitor was not toxic in primary osteoclast cells up to 1000 nM. CKI-8 did not affect alkaline phosphatase activity as well the mineralization induced by Saos-2 cells and by primary osteoblasts. CKI-13 decreased by 35% the mineralization induced by Saos-2 cells while it did not on mineralization induced by primary osteoblasts. Addition of CKI-13 decreased alkaline phosphatase activity by around 20% (Saos-2 cells) and 45% (primary osteoblasts). Bone resorption on bovine slices decreased significantly with 10 nM of CKI-13, with 100 nM of CKI-8 and commercial inhibitor E64. Our findings indicated that CKI-8 and CKI-13 inhibited bone resorption and affected the mobility of osteoclast. To monitor directly the PPi hydrolytic activity by alkaline phosphatase, we developed an infrared (IR) assay taking the advantage to use natural substrate under physiological pH in matrix vesicles and in living cells. PPi band located at 1107 cm-1 (∑= 2158 ± 211 M-1.cm-1) and Pi bands located at 1076 cm-1 (∑= 1346 ± 116 M-1.cm-1) and at 991 cm-1 (∑= 493 ± 49 M-1.cm-1) served to measure the substrate and the product concentrations

The objective of this study is to perform Optically Stimulated Luminescence (OSL) dating on the ceramic samples from different parts of the Laodikeia by using Infra Red Stimulated Luminescence (IRSL) on polyminerals. As a first step, a literature survey has been done about the dating system and the methodology of dating. The calibration of the system was done before carrying out the experiments. The six ceramic samples were collected from the site and dated. The mineral compositions of the samples were examined by X-ray Diffraction Analysis, which showed that all samples contain quartz, feldspars, calcites and together with other minerals. The equivalent dose was found by using Multiple Aliquot Additive Dose (MAAD) and Multiple Aliquot Regenerative Dose (MARD) techniques using Infra Red diode array of the system that gave the IRSL ages for samples. Alpha counter measured the dose components of uranium and thorium contributions to the annual dose. The potassium concentration was determined by Atomic Emission Spectrometry. The cosmic ray component of annual dose was evaluated by the Al2O3:C Thermoluminescence Dosimeter (TLD) discs which have been placed and kept for 8 and 11 months in the site. From the data the IRSL ages were calculated for six ceramic samples LDKY-1, LDKY-2, LDKY-3, LDKY-4, LDKY-5 and LDKY-6 with the help of the OSL system software. The IRSL ages for these samples, in the given order, are 737 &plusmn / 60, 1563 &plusmn / 120, 1445 &plusmn / 110, 1602 &plusmn / 120, 1034 &plusmn / 80 and 1034 &plusmn / 80 years by using MAAD technique. The IRSL ages for the same samples are 870 &plusmn / 60, 1550 &plusmn / 120, 1440 &plusmn / 110, 1600 &plusmn / 120, 1030 &plusmn / 80 and 1030 &plusmn / 70 years by using MARD technique.