Container grown perennials are a popular product offered by nurseries and greenhouses and included in their production but little research has been reported on proper overwintering techniques for herbaceous perennials and ornamental grasses. In the first experiment rooted liners of Pennisetum alopecuroides, Pennisetum "Hameln" and Pennisetum "Little Bunny," were potted. Treatments included, utilizing two overwintering covers, two fertilizer rates (low or high) and two substrate moisture contents (wet or dry). Covering with either a double layer of Dewitt N-Sulate™ insulation fabric or a double layer of Dewitt N-Sulate™ insulation fabric and a single sheet of 4 mil white polyethylene plastic on top of the insulation fabric, wet substrate treatments, low fertility rates and combinations of both, improved survival and vigor for all three tested Pennisetum species and cultivars. In the second experiment, rooted liners of P. alopecuroides, P. "Hameln" and P. "Little Bunny," were potted. Treatments included, two transplanting times (young or old), two fertilizer rates (low or high) and two substrate moisture contents (wet or dry) at the UHC and Poplar Ridge Nursery (Montross, VA) (PR). Vigor was improved for P. alopecuroides (at PR) and P. "Little Bunny" (at both locations) with the young transplanting time. In the third experiment, older plant material of P. alopecuroides, P. "Hameln" and P. "Little Bunny," were subjected to fertility treatments of no additional fertilizer or top-dressed at a low, medium or high rate . A high fertility rate reduced survival and vigor for P. "Little Bunny." In the fourth experiment rooted liners of Echinacea purpurea "Hot Papaya," Echinacea purpurea "Milkshake," Gaillardia x grandiflora "Gallo Peach," Heuchera x villosa "Pistache," Heuchera x villosa "Brownies," P. alopecuroides, P. "Cassian," P. "Hameln" and P. "Little Bunny," were potted and overwintered at the UHC or Poplar Ridge Nursery (Montross, VA) (PR) or Riverbend Nursery, Inc. (Riner, VA) (RB). Treatments included, utilizing two overwintering covers, two fertilizer rates (low or high) and two substrate moisture contents (wet or dry). Vigor at the UHC, was reduced with the high fertility rate for E. "Hot Papaya" and H. "Brownies." A double layer of Dewitt N-Sulate™ insulation fabric and white polyethylene plastic on top of the cover, in combination with the wet substrate moisture treatment improved vigor of E. "Hot Papaya."A double layer of Dewitt N-Sulate™ insulation fabric in combination with the wet substrate moisture content and the high fertility rate reduced P. "Cassian" vigor. No overwintering cover reduced P. "Hameln" vigor. No overwintering cover and the high fertility rate reduced P. "Little Bunny" vigor. Vigor at PR was improved with the high fertility rate for E. "Milkshake," G. "Gallo Peach" and H. "Brownies." At RB, a double layer of Dewitt N-Sulate™ insulation fabric in combination with the low fertility treatment and no cover in combination with the high fertility treatment reduced vigor for E. "Milkshake" and P. "Little Bunny," respectively. No cover in combination with the wet substrate moisture treatment reduced vigor for G."Gallo Peach." / Master of Science

In order to predict the strength of shear wall with cold-formed steel framing members, analytical models were reviewed. Multiple analytical models were studied, as well as twenty-one connection tests were performed. The connection tests consist of 50-ksi cold-formed steel framing track, different fastening configurations, and different sheathing thicknesses (1/8" and 1/2"). No.12 screw resulted in the highest peak load of all fastening configurations, while the rivet connection had the lowest peak load. In addition, failure modes were observed after conducting the connection tests including shear in fastening, screw pullout, and bearing in the sheathing. However, only the rivet and No.10 screw fastening configurations were used in the prediction analysis of the shear wall by the elastic model. Six shear wall tests were conducted on both panels (1/2"and 1/8" thickness). After doing the comparison between the experimental and the elastic model, the percentage difference for the 1/8" and the 1/2" polymer composite panels (3''along the edge and 6''along the chord stud), was very small. It was 6.2% for the 1/8" and 2.96% for the 1/2" panels. This means the analytical model can predict the shear wall peak load. However, the percentage difference was slightly higher being 7.4% for the 1/2" polymer composite panels with 6" along the perimeter with the 12" at the chord stud. After comparing the experimental values to the predicted value of shear walls, it was concluded that this model is the most appropriate analytical method for predicting the shear wall capacity framed with cold-formed steel sheathed with polymer composite panels. Many of these configurations were used in a prototype shelter that was constructed and built at the structural testing laboratory at the University of North Texas.

The Cold War was a time of extreme conformity, with an equally extreme reaction against forced conformity. Representations of such reactions were not to be omitted in the literature of the time. Throughout the novels, the characters and society itself are repressed into an alternate state of being. This investigation analyzes the role that technology plays in this process in Fahrenheit 451, Sirens of Titan, 1984, Lord of the Flies, and A Clockwork Orange. The novels were all written during the Cold War and follow a dystopian society. Society is controlled and maintained in its respective disarray through the utilization of technology, whether it be pushed down upon them by their governments or by themselves. Through close analysis of the novels themselves and existing discourse related to the topic, it becomes evident that technology is able to manipulate and dictate the lives of people, diminishing their individualism. A dichotomy between creative expression and technology arises in all of the studied novels, pointing to the significance of individualism and its existence through creativity. This investigation concludes that such acts of expression, including creative writing and nonconformist acts, are vital to maintaining a stable societal system. The literature points to the ultimate evil that arises from technology and the power that inevitably comes with it, warning that humanity itself may be lost without the existence of free will and individual thought.

For many years, an equation to express the relationship of stress to strain has been desired, and recently a study of the change of properties resulting from the cold working of a metal has assumed important proportions. For stresses below the elastic limit, Hooke's law and Poisson's ratio are applicable, but above the elastic limit relation to stress to strain follows a different law. Copper and steel are both ductile materials, and it is, therefore, logical to assume that they will show similarity of characteristics. Copper and steel have individual peculiarities, but copper appears to be erratic in its behavior. For example, the modulus of elasticity of steel varies, according to some law resembling a hyperbolic function of the cold working. However, copper does not follow a similar law. The investigation of cold worked copper is of importance in practice. In the manufacture of copper wire, for instance, it is desirable to know how the elastic limit, the maximum load, and the plastic working limit vary as the degree of cold drawing increases. / M.S.

Submitted to the Faculty of Health at the Durban University of Technology in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Department of Chiropractic, Durban University of Technology, Durban, South Africa, 2015. / Background: Cryotherapy is often the first option in treating acute conditions and can be applied in various forms including ice packs and cooling gels. Cooling gels are easy to use and readily available making them popular with consumers. They can also contain additional ingredients which can assist with inflammation, making them ideal for musculoskeletal disorders. A cooling gel containing menthol and anti-inflammatory herbs is available in pharmacies nationwide in South Africa, but has not been clinically investigated. This gel is often used in the treatment of acute injuries such as low back pain but its effectiveness in treating this condition has not yet been verified. Objectives: To determine the effectiveness of a menthol cooling gel combined with anti-inflammatory herbs compared to a menthol gel and a placebo gel in the treatment of acute non-specific low back pain. Method: A double-blinded placebo controlled clinical trial (n = 60) was conducted. Each participant was randomly allocated into one of three treatment groups consisting of a minimum of 20 participants between the ages of 18 and 40 who met the study criteria. Informed consent was obtained from the participants prior to their participation in the study. At the initial consultation baseline measurements (pain rating, disability and pressure pain threshold) were taken and the respective treatments (menthol with anti-inflammatory herb, menthol or placebo gel) were administered. Participants were instructed on how to apply the gel at home and were requested to apply it three times a day for one week. Statistical analysis was performed using repeated measures ANOVA for inter- and intra-group analysis with one way ANOVA and chi square tests being used to compare baseline values. A p-value < 0.05 was considered to be statistically significant. The study received ethical clearance from the Durban University of Technology Institutional Research Ethics Committee (REC 81/13). Results: No significant differences were observed between the groups at baseline assessment, indicating that the groups were comparable. Participants were instructed on how to apply the gel at home and were requested to apply it three times a day for one week. Follow up appointments for data collection was scheduled at days three or four and six. No statistically significant differences were observed between the three groups over time for pain (p = 0.95), disability (p = 0.903) or pressure-pain threshold (p = 0.824), with all groups showing improvement. All three groups showed clinically significant changes in pain from moderate to mild over the duration of the study but no clinically significant changes were noted in terms of pressure-pain threshold and disability. Conclusion: The results indicate that irrespective of whether or not the gel contains active ingredients there was an improvement in acute low back pain. Further research needs to be conducted to determine if tissue depth and the concentration of the active ingredients such as menthol are factors affecting the efficacy of this gel.

Background: (Papers I and II) The objectives were to first determine incidence and contributing factors to cold-related injuries in northern Sweden, both those that led to hospitalization and those that led to fatality.  (Papers III and IV) A further aim was to assess post-cooling hand-rewarming responses and effects of training in a cold environment, both on fingertip rewarming and on function of the autonomic nervous system, to evaluate if there was adaptation related to prolonged occupational cold exposure. Methods:  In a retrospective analysis, cases of accidental cold-related injury with hospital admission in northern Sweden during 2000-2007 were analyzed (Paper I).  Cases of fatal hypothermia in the same region during 1992-2008 were analyzed (Paper II).  A cohort of volunteers was studied before and after many months of occupational cold exposure. Subject hand rewarming response was measured after a cold hand immersion provocation and categorized as slow, moderate or normal in rewarming speed.  This cold provocation and rewarming assessment was performed before and after their winter training.  (Paper III).  Heart rate variability (HRV) was analyzed from the same cold provocation/recovery sequences (Paper IV). Results:  (Paper I) For the 379 cases of hospitalization for cold-related injury, annual incidences for hypothermia, frostbite, and drowning were 3.4/100,000, 1.5/100,000, and 1.0/100,000 inhabitants, respectively.  Male gender was more frequent for all categories.  Annual frequencies for hypothermia hospitalizations increased during the study period.  Hypothermia degree and distribution of cases were 20 % mild (between 32 and 35ºC), 40% moderate (31.9 to 28ºC), and 24% severe (&lt; 28ºC), while 12% had temperatures over 35.0ºC.  (Paper II) The 207 cases of fatal hypothermia showed an annual incidence of 1.35 per 100,000 inhabitants, 72% in rural areas, 93% outdoors, 40% found within 100 meters of a building.  Paradoxical undressing was documented in 30%.  Ethanol was detected in femoral vein blood in 43%. Contributing co-morbidity was common including heart disease, previous stroke, dementia, psychiatric disease, alcoholism, and recent trauma.  (Paper III) Post-training, baseline fingertip temperatures and cold recovery variables in terms of final rewarming fingertip temperature and vasodilation time increased significantly in moderate and slow rewarmers.  Cold-related injury (frostbite) during winter training occured disproportionately more often in slow rewarmers (4 of the 5 injuries).  (Paper IV) At ‘pre- winter-training’, normal rewarmers had higher power for low frequency and high frequency heart rate variability.  After cold acclimatization (post-training), normal rewarmers showed lower resting power values for the low frequency and high frequency heart rate variability components.  Conclusions: Hypothermia and cold injury continues to cause injury and hospitalization in the northern region of Sweden.  Assessment and management is not standardized across hospitals.  With the identification of groups at high risk for fatal hypothermia, it should be possible to reduce the incidence, particularly for highest risk subjects; rural, living alone, alcohol-imbibing, and psychiatric diagnosis-carrying citizens.  Long-term cold-weather training may affect hand rewarming patters after a cold provocation, and a warmer baseline hand temperature with faster rewarming after a cold provocation may be associated with less general risk for frostbite.  Heart rate variability results support the conclusion that cold adaptation in the autonomic nervous system occurred in both groups, though the biological significance of this is not yet clear.

Este trabalho relata o processo de fotoionização associativa em átomos ultrafrios de sódio confinados por uma armadilha magneto-óptica. O comportamento da constante de reação Kpai é medido em função da intensidade dos feixes de aprisionamento, também em função da freqüência de um segundo laser. Este estudo mostrou que fotoionização ocorre em um processo de várias etapas e mostrou a importância da emissão espontânea em colisões ultrafrias. Nós confirmamos experimentalmente pela primeira vez o processo de blindagem óptica, o qual evita a interação dos átomos com a luz incidente. O entendimento deste processo é relevante se desejar-se aumentar o número e a densidade das amostras atômicas aprisionadas. / This works reports on the photo-associative ionization process in ultracold sodium atoms confined in a magneto optical trap. The behavior of the rate constant Kpai is measured as a function of the trapping beams intensity, and as a function of the frequency of a second laser. This study showed that photo-associative ionization occurs in a multi-step process and also showed the importance of spontaneous emission in ultracold collisions. We experimentally confirmed for the first time the Optical Shielding process which prevents atoms from approaching due to repulsive states induced by the interaction of the atoms with the incident light. The understanding of this process is relevant if one intends to increase the number and density of trapped atomic samples.

Neste trabalho, apresentamos uma montagem experimental capaz de aprisionar átomos de K e Rb simultaneamente em uma armadilha óptica de dipolo cruzada. Contudo, para atingir este feito foi necessário, durante o desenvolvimento do projeto, estudar cada espécie atômica de forma isolada. Assim, desenvolvemos uma técnica inédita para carregar uma armadilha de dipolo diretamente de uma armadilha magneto-óptica de 39K, constatando a importância da estrutura hiperfina do estado 4P3/2 no processo de carregamento. Também observamos e explicamos o processo de fotoassociação de Rb devido ao laser em 1071 nm, inclusive a diferença isotópica entre 85Rb e 87Rb. Na sequência, realizamos o carregamento duplo com K e Rb na armadilha e observamos a fotoassociação de KRb. Um modelo teórico simples prevê a distribuição dos níveis vibracionais obtidos. O mesmo modelo abre caminho para um possível bombeamento óptico para a produção e acúmulo de moléculas de KRb no estado X1&Sigma;+ (v = 0). / In this paper, we present an experimental setup to simultaneously trap atoms of K and Rb in a crossed optical dipole trap. This accomplishment required the individual study of each atomic species during the project development. This allowed the development of a new technique for loading a dipole trap directly from a magneto-optical trap of 39K, providing evidence of the importance of the hyperfine structure of the state 4P3/2 in the loading process. We also observe and explain the photoassociation process of Rb2 due to the dipole trap laser at 1071 nm, including an isotopic difference between 85Rb and 87Rb. In the sequence, we performed dual species loading of K and Rb and observed the photoassociation process of KRb. A simple theoretical model predicts the final distribution of vibrational levels obtained. The same model provides a potential path to optically pump the molecules and accumulate them in the molecular ground state X1&Sigma;+ (v = 0) for KRb.

The majority of the structural weight of many common commercial aircrafts is composed of high strength aluminum alloys. The properties of high performance aluminum alloys such as a high strength to weight ratio (specific strength), ease of recycling, crash energy absorption capacity, and corrosion resistance make them ideal for use in the aerospace field. As a result of the high performance nature of the parts and specific properties of the materials, manufacturing requires intricate casting, precision machining, and specific heat treatments – which results in expensive components. As a result of its excellent corrosion resistance properties, pure aluminum coatings are commonly used in the aerospace field for corrosion protection of steel, aluminum alloy components, and titanium alloy components. The common method to deposit these coatings is called ion vapour deposition (IVD). These IVD aluminum coatings provide the coating adhesion, coverage, thickness, and corrosion resistance required to protect the part. The present study was motivated by the potential use of the cold gas dynamic spray (CGDS) process to repair a) damaged aluminum alloy aerospace parts and b) damaged pure aluminum IVD coatings. The primary research objective was to successfully produce these repairs using commercially available aluminum alloy feedstock powders deposited with commercially available CGDS equipment. This work was treated as prequalification work for The Boeing Company to commercialize this process and therefore the repairs aim to meet the same standards (military and industrial) required of the original aluminum alloy parts and IVD aluminum coatings. The use of CGDS was shown in this research to be a very promising as a process for the restoration of aluminum alloy aerospace components. The adhesion strength of the repaired aluminum components was found to be well above the accepted range for thermally sprayed repairs according to industrial standards. The repairs were subjected to a highly corrosive environment and showed only minor pitting. These sites could be reduced in the future with improved machining techniques and attention to surface detail prior to exposure to the salt fog. The only requirement that the repaired components did not meet was for the wear properties of the anodized layer, measured thought Taber abrasion testing. The results of this test, at times, approached the desired values, and it is believed that, in the future, the quality and consistency of the coatings could be improved and the test would meet industrial standards. The results of this research show that the use of CGDS as a process for the restoration of damaged aluminum IVD coatings is possible and is a promising alternative to conventional methods. The CGDS coatings were scrutinized to the same level as required of IVD coatings when they replaced toxic cadmium coatings in the late 1980s. The coating adhesion, demonstrated through glass bead abrasion and strip rupture testing, was shown to meet the current industrial standards. The corrosion testing of the repairs resulted in no visible red rust of the steel components, even when the steel was exposed.

La réparation des composants en alliages légers est un processus clés dans le domaine de l’aéronautique. Ces alliages sont abondamment utilisés dans les constructions aéronautiques notamment pour des composants à forte valeur ajoutée. Leur utilisation combinée à une optimisation de la conception des pièces permet de disposer de produits satisfaisants aux exigences de masse, de coût et de performances. Cependant l’utilisation de ces pièces est limitée dans le temps car divers endommagements peuvent survenir aussi bien lors de leurs manipulations que lors de leurs utilisations en service. Des solutions de retouches existent mais ne permettent pas toujours de redonner leur intégrité aux zones affectées. Ces limitations sont à l’origine d’un fort taux de rebut parmi les pièces à forte valeur ajoutée.Les multiples avantages du procédé Cold Spray en font un candidat idéal pour la projection de revêtements adaptés aux composants en alliages légers mis en oeuvre en aéronautique, que ce soit dans une logique de protection, de retouche ou de réparation. Il s’agit de reconstruire la pièce par un revêtement aux caractéristiques les plus proches possibles de celles du matériau de base. Ce travail de thèse consiste à optimiser l’ensemble des paramètres du procédé de projection dynamique à froid (Cold Spray) pour plusieurs couples substrat-revêtement combinant différents alliages d'aluminium, de magnésium et des composites à matrice métallique à base aluminium.La première étape a consisté à optimiser les paramètres principaux du procédé Cold Spray afin de s’affranchir du phénomène de colmatage pouvant intervenir au sein de la section divergente de la buse de projection. Ce phénomène a pour effet de diminuer la vitesse des particules, les revêtements obtenus devenant alors assez poreux. Une étude s’est ensuite focalisée sur l’optimisation de l’adhérence des couples substrats-revêtements. Il a été démontré le rôle primordial de la préparation de surface dans l’adhérence des revêtements où l’ancrage mécanique apparaît prépondérant. Enfin, une étude originale a été conduite pour mettre au point une méthodologie pour recharger localement une zone défectueuse sans avoir à recouvrir toute la surface du substrat. Une programmation hors ligne du robot a été employée afin de recouvrir deux types de défaut pré-usinés sur des blocs d’alliage d'aluminium. Les résultats sont satisfaisants avec des gains en temps de projection et des dépôts sans défaut après usinage. / The repair of light alloy parts is a major issue in aeronautics. Aluminum alloy and magnesium alloy are widely used in aircraft parts, especially for high value-added components. Their use combined to optimizing design allows to have satisfactory products meeting mass, cost and performance requirements. However, like any other life-limited components, various damages can occur not only during handling procedure but also while operating. Rectification solutions exist but do not always comply with requirements. These limitations entail high scrap rates among high value-added parts.The various advantages of the cold spray process make it an ideal candidate for suitable coatings for light alloy aircraft components as protective, retouching or repair methods. The aim is to rebuild the damaged part by a coating whose characteristics are closest to those of primary materials. This thesis proposes to optimize different cold spray parameters for several substrate-coating pairs combining different aluminum alloys, magnesium alloys and aluminum alloy-based metal matrix composites.The first step was to optimize the main parameters of cold spray process to prevent clogging phenomenon that may occur in the expansion part of the nozzle. It decreases particle kinetics and promotes porous coating. Then, adhesion optimization of substrate-coating couples was investigated. The substrate surface preparation is a key factor on coating adhesion, where the mechanical anchoring appears essential. Finally, an innovative study was conducted to develop a method to cover locally surface defects. Offline programming trajectories were used to fill up two kinds of pre-machined defaults on aluminum alloy blocks. Results are in good agreement with spray time savings and defect free coatings after machining.