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Syfte: Målsättningen med studien är att hos friska kvinnor utvärdera om intensiv tuggning leder till en proprioceptiv allodyni i massetermuskulaturen. Följande hypoteser testades i studien: 30 minuters intensivt tuggande leder till (1) ökad trötthet och smärta, (2) sänkt smärttröskel, (3) ökad vibrotaktil känslighet (4) samt träningsvärk i massetermuskulaturen bilateralt. Material och Metod: 16 friska kvinnor (medelålder 25.8 ± 5.0 år) deltog i studien som bestod av två 60-minuters sessioner med 24-timmars uppföljning. Vid ena sessionen tuggade försökspersonerna på ett grekiskt tuggummi (Masticha Chios) i 5-minuters intervaller under 30 minuter, och vilade vid den andra sessionen. En vibrameter användes för att mäta vibrationströskel, upplevd vibrationsintensitet och upplevd vibrationsobehag. Upplevd trötthet och upplevd smärtintensitet värderades enligt en visuell analog skala 0-100 mm (VAS skala). Smärttröskeln mättes med en algometer som applicerades på massetermuskelns fäste. Två vägs variansanalys användes för att testa utfallsvariabler för upprepade mätningar och Dunnett’s posthoc-test. Resultat: En signifikant skillnad kunde ses mellan tuggning och icke tuggning för vibrationströskeln (P < 0.001); upplevda tröttheten (P < 0.001); smärttröskeln (P < 0.01); upplevda vibrationsobehaget (P < 0.05). Inga signifikanta skillnader observerades för upplevd smärta och upplevd vibrationsobehag. Däremot kunde en signifikant ökning ses över tid för vibrationströskeln och den upplevda tröttheten. Konklusion: Våra fynd indikerar att det ej finns något samband mellan intensiv tuggning och träningsvärk i massetermuskulaturen. Däremot resulterade tuggningen i ökad muskeltrötthet och vibrationsobehag, samt signifikant högre trösklar för smärta och vibration under försökets gång. Proprioceptiv allodyni kunde ej påvisas. / Aims: To evaluate if intense chewing leads to proprioceptive allodynia in the masseter muscle, and test if (1) pain and fatigue are increased after intense chewing, (2) pressure pain thresholds are decreased after intense chewing, (3) vibration thresholds are increased after intense chewing, (5) intense vibrations exacerbate pain after intense chewing. Materials and Methods: 16 healthy female volunteers (mean age 25.8 ± 5 years) participated in two 60-minute sessions, each with 24-hour follow-ups. In the first session, the subjects were instructed to chew on a viscous chewing gum (Masticha Chios). In the other session the participant were assigned a control task where no chewing was performed. Perceived intensity of vibration and perceived discomfort were assessed with a Vibrameter® on a 0-50-100 visual analog scale (VAS). Two 0-100 mm visual analog scales measured pain intensity and perceived fatigue. The pain threshold was measured with an electronic algometer. These variables were measured to assess delayed onset muscle soreness. All measurements were made on the masseter muscles. Two-way analysis of variance for repeated measures and Dunnett’s post hoc test was used to test for significant alterations in the outcome variables. Results: Significant differences were observed between chewing and no-activity for vibration threshold (P<0.001); perceived fatigue (P<0.001); pain threshold (P<0.01) and vibration discomfort (P<0.05). No significant differences were seen for perceived pain and perceived intensity of vibration. A significant increase over time could only be observed for vibration threshold (P<0.01) and perceived fatigue (P<0.05). Conclusion: Our findings suggest that there is no relation between intense chewing and delayed onset muscle soreness in the masseter muscles. Intense chewing evoked moderate levels of fatigue and discomfort, and a hypoalgesia to mechanical stimulation, and reduced vibrotactile sensitivity.

Helical heating coils are widely used in most conventional electric stoves for many years, these heating coils can reach 600-700°C, which is higher than the ignition point of oil and grease (about 400°C), leading to many fires. Pioneering Technology Inc. has developed a Safe-T Element plate to address such problem. The Safe-T Element plate is manufactured from Gray Cast Iron. However, these plates deform during its use. This study was carried out to investigate the current Safe-T Element design, both experimentally and numerically, in order to determine the root causes behind the deformation problem of the plate, and to suggest changes to the existing design in order to limit its distortion to acceptable targets. A chemical analysis was carried out to establish the type of material of the Safe-T Element plate. Chemical analysis showed that the material of the plate is cast iron. The microstructure of the plate was tested in order to examine its type and homogeneity. Tensile testing was carried to establish the grade of the material, and to calculate the value of its young's modulus and yield strength. Tensile testing indicated that the material of the Safe-T Element plate is close to Gray Cast Iron Class 40. Differential scanning calorimetry testing was carried out to investigate thermal stability of the plate material. This test indicated that material is thermally stable. Thermal cycling testing indicated that the root cause of the deformation problem is elastic thermal buckling. Temperature uniformity tests were carried out. More than 100°C temperature variation in the radial direction was observed. To address the distortion of the plate, an optimum geometry has been suggested based on the findings of the numerical investigation by removing the outer ring from the original design of the plate. / Thesis / Master of Applied Science (MASc)

Yes / This paper presents an experimental study into the axial compressive behaviour of self-compacting concrete filled elliptical steel tube columns. In total, ten specimens, including two empty columns, with various lengths, section sizes and concrete strengths were tested to failure. The experimental results indicated that the failure modes of the self-compacting concrete filled elliptical steel tube columns with large slenderness ratio were dominated by global buckling. Furthermore, the composite columns possessed higher critical axial compressive capacities compared with their hollow section companions due to the composite interaction. However, due to the large slenderness ratio of the test specimens, the change of compressive strength of concrete core did not show significant effect on the critical axial compressive capacity of concrete filled columns although the axial compressive capacity increased with the concrete grade increase. The comparison between the axial compressive load capacities obtained from experimental study and prediction using simple methods provided in Eurocode 4 for concrete-filled steel circular tube columns showed a reasonable agreement. The experimental results, analysis and comparison presented in this paper clearly support the application of self-compacting concrete filled elliptical steel tube columns in construction engineering practice.

No / In order to investigate the eccentric compression behaviors of steel-FRP composite bar (SFCB) reinforced concrete (RC) columns subjected to chloride corrosion, the mechanical experiments of chloride corroded SFCBs and SFCBs RC eccentric compression columns were conducted. The effect of reinforcement type and ratio, eccentricity, slenderness, stress level and corrosion duration on bearing capacity, deformation, crack and failure pattern were investigated. The results showed that the strength retention ratio of reinforcement decreases with the increase of corrosion duration, the ultimate strengths of steel rebar, SFCB and FRP rebar decreased by 12.2%, 9.9% and 3.6%, respectively, when compared with those of uncorroded counterparts. With the increase of steel content of reinforcement, the load bearing capacity of eccentric compression RC column increases while the deformation decreases gradually. The load bearing capacity of corroded steel, SFCB and FRP RC columns maximally decreased by 16.6%, 12.4% and 7.2%, respectively, when compared with those of uncorroded counterparts. Based on the simplified materials constitutive relations and reasonable basic assumptions, formulae for discriminate failure mode, moment magnification factor and bearing capacity were developed. The predicted failure pattern, moment magnification factor and bearing capacity are in good agreement with the test results, confirming the validity of the proposed formulae, the results can be used as a reference for engineering application. / High-End Foreign Experts Project of Ministry of Science and Technology, China (G2022014054L), the Natural Science Foundation of Jiangsu Province, China (BK20201436), the Science and Technology Project of Jiangsu Construction System (2018ZD047, 2021ZD06), the Science and Technology Project of Gansu Construction System (JK2021-19), the Opening Foundation of Jiangsu Province Engineering Research Center of PrefabricatedBuilding and Intelligent Construction (2021), the Science and Technology Cooperation Fund Project of Yangzhou City and Yangzhou University (YZ2022194, YZU212105), the Science and Technology Project of Yangzhou Construction System (2022ZD03, 202204), the Nantong Jianghai (226) talents project, the Blue Project Youth Academic Leader of Colleges and Universities in Jiangsu Province (2020).

Le tournage de superfinition est très spécifique avec une profondeur de passe de l’ordre de 0.05mm et une avance de 0.05mm/tour et permet d’obtenir des surfaces dont la précision et la rugosité sont équivalents à ce que l’on pourrait obtenir par rectification. Cependant, ce procédé est fortement influencé par les caractéristiques dynamiques du système usinant. Le but de nos travaux est de comprendre comment les caractéristiques dynamiques du système Pièce / Outil / Machine (P.O.M.) influencent la qualité de surface obtenue en superfinition à l’outil coupant. Dans un premier temps, nous avons défini, en nous appuyant sur la méthode normalisée du Couple Outil Matière (C.O.M.), des conditions de coupe acceptables et stables. Ensuite, une analyse fréquentielle nous a permis d’identifier trois éléments du système P.O.M. comme sources de vibrations remarquables, à savoir la machine elle-même, la fréquence de rotation de la broche et l’outil utilisé. Puis, nous avons mis en place une démarche expérimentale lourde afin d’évaluer l’influence des sources identifiées sur des critères d’état de surface et sur les vibrations mesurées au niveau de l’outil coupant. Enfin nous avons abordé l’étude des corrélations existantes entre les vibrations et l’état de surface généré en tournage de superfinition / The superfinishing in turning is very specific, depth of cut about 0.05mm and feed in the order of 0.05mm/rev and allows to produce surfaces with precision and roughness equivalent to grinding process. However, this process is strongly influenced by the dynamic characteristics of the machining system. The aim of our work is to understand how dynamic characteristics of the Part/Tool/Machine (P.T.M.) system influence the surface quality obtained in superfinishing with cutting tool. Initially, we defined acceptable and stable cutting conditions by using the standardized method of the Couple tool-matterial. Then, a frequential analysis enabled us to identify three remarkable sources of vibrations in the P.T.M. system that are the machine tool, the spindle frequency and the tool. Then, we set up an experimental study in order to evaluate the influence of the identified sources of vibrations on surface quality and on the vibrations measured on the cutting tool. Finally we studied the correlations between the vibrations and the surface quality obtained by superfinishing turning

Film cooling is a cooling technique widely used in high-performance gas turbines to protect turbine airfoils from being damaged by hot flue gases. Film injection holes are placed in the body of the airfoil to allow coolant to pass from the internal cavity to the external surface. The ejection of coolant gas results in a layer or “film” of coolant gas flowing along the external surface of the airfoil. In this study, a new cooling scheme, mist/air film cooling is proposed and investigated through experiments. Small amount of tiny water droplets with an average diameter about 7 μm (mist) is injected into the cooling air to enhance the cooling performance. A wind tunnel system and test facilities were build. A Phase Doppler Particle Analyzer (PDPA) system is employed to measure droplet size, velocity and turbulence. Infrared camera and thermocouples are both used for temperature measurements. Mist film cooling performance is evaluated and compared against air-only film cooling in terms of adiabatic film cooling effectiveness and film coverage. Experimental results show that for blowing ratio M=0.6, net enhancement in adiabatic cooling effectiveness can reach 190% locally and 128% overall along the centerline. The general pattern of adiabatic cooling effectiveness distribution of the mist case is similar to that of the air-only case with the peak at about the same location. The concept of Film Decay Length (FDL) is proposed to quantitatively evaluate how well the coolant film covers the blade surface. Application of mist in the M=0.6 condition is apparently superior to the M=1.0 and 1.4 cases due to the higher overall cooling enhancement, the much longer FDL, and wider and longer film cooling coverage area. Based on droplet measurements through PDPA, a profile describing how the airmist coolant jet flow spreads and eventually blends into the hot main flow is proposed. A sketch based on the proposed profile is provided. This profile is found to be well supported by the measurement results of Turbulent Reynolds Stress. The location where a higher magnitude of Turbulent Reynolds Stress exists, which indicates higher strength of turbulent mixing effect, is found to be in the close neighborhood of the edge of the coolant film envelope. Also the separation between the mist droplets layer and the coolant air film is identified through the measurements. In other words, large droplets penetrate through the air coolant film layer and travel further over into the main flow. Based on the proposed air-mist film profile, the heat transfer results are reexamined. It is found that the location of optimum cooling effect is coincident with the starting point where the air-mist coolant starts to bend towards the surface. Thus the data suggests that the “bending back” film pattern is critical in keeping the mist droplets close to the surface which improves the cooling effectiveness for mist cooling.

In the modern advanced gas turbines, the turbine inlet temperature may exceed 1500°C as a requirement to increase power output and thermal efficiency. Therefore, it is imperative that the blades and vanes are cooled so they can withstand these extreme temperatures. Film cooling is a cooling technique widely used in high-performance gas turbines. However, the film cooling effectiveness has almost reached plateau, resulting in a bottleneck for continuous improvement of gas turbines' efficiency. In this study, an innovative cooling scheme, mist film cooling is investigated through experiments. A small amount of tiny water droplets with an average diameter about 10-15 µm (mist) is injected into the cooling air to enhance the cooling performance. A Phase Doppler Particle Analyzer (PDPA) system is used for droplet measurements. Mist film cooling performance is evaluated and compared against air-only film cooling. This study continues the previous work by (a) adding fan-shaped holes and comparing their cooling performance with the round holes, (b) extending the length of the test section to study the performance farther downstream the injection holds, and (c) using computational simulation to investigate the feasibility of transporting mist to the film cooling holes through gas turbine inside passages. The results show that, with an appropriate blowing ratio, the fan-shaped holes performs about 200% better than round holes in cooling effectiveness and adding 10% (wt.) mist can further enhance cooling effectiveness 170% in average. Farther downstream away from the injection holes (X/D> 50), mist cooling enhancement prevails and actually increases significantly. PDPA measurements have shed lights to the fundamental physics of droplet dynamics and their interactions with thermo-flow fields. These experimental results lead to either using lower amount of cooling air or use fewer number of cooing holes rows. This means higher gas turbine power output, higher thermal efficiency, and longer components life which will reflect as a cheaper electricity bill. Computational Fluid Dynamics (CFD) showed that it is feasible to transport the water mist, with initial diameters ranging from 30 µm-50 µm and mist ratio of 10-15%, to the cooling holes on the surface of the turbine vanes and rotors to provide the desired film cooling. Key words: Gas Turbines, Heat Transfer, Film / mist Cooling, Experimental Study, Mist Transport, CFD, PDPA.

A obesidade na infância e adolescência tem aumentado de forma bastante acentuada, e quando observada nos primeiros anos de vida leva um maior risco para hipercolesterolemia, hipertrigliceridemia e alterações cardiovasculares na vida adulta. Uma correlação positiva tem sido observada entre a BMI (Body Mass Index, ou índice de massa corporal) e alterações metabólicas e hematológicas, implicando em alterações na capacidade de cicatrização, na defesa imunológica e celular e no desenvolvimento de diferentes patologias. O objetivo deste estudo foi avaliar os efeitos das fases iniciais da hipercolesterolemia, ou seja, nas idades infantil e juvenil e com pequeno aumento de colesterol, sobre os tecidos bucais e a capacidade de cicatrização. A Ratos Wistar (40g de peso) foi oferecido uma ração preparada com 1% de aumento (em peso) de colesterol + 20% de gordura (óleo de soja) por um período de 2 e 6 semanas para avaliação dos tecidos bucais. Após 2 semanas do uso da ração enriquecida com colesterol foram realizadas feridas cirúrgicas no dorso dos animais para avaliação da cicatrização. Ao final dos tratamentos propostos, os animais foram sacrificados, e colhidas as peças utilizadas (sangue, pele, língua, palatos e região gengival). O sangue coletado foi centrifugado e o soro foi utilizado para avaliação das lipoproteínas - colesterol total, HDL, LDL, VLDL e triglicérides em espectrofotômetro de absorbância. As peças colhidas foram levadas para fixação e descalcificação de acordo com a necessidade, processadas para inclusão em parafina, cortadas com 6 &micro;m de espessura, montadas em lâminas de vidro e coradas com hematoxilina e eosina. Essas peças foram utilizadas para avaliação histológica dos tecidos e do processo de cicatrização, por meio de técnicas morfométricas. Os dados colhidos foram apresentados em valores médios, e as diferenças analisadas por testes estatísticos adequados para a comparação entre as amostras. Nossos resultados mostram que a hipercolesterolemia provocou alterações em tecidos epiteliais e que esses efeitos parecem ser progressivos, ou seja, se tornam mais expressivos com o uso continuado de alimentação com índice de colesterol aumentado, e que existe um aparente atraso no processo de cicatrização nos indivíduos que utilizam dieta hipercolesterolêmica. Consideramos que essas alterações podem tornar esses indivíduos mais suscetíveis a alterações bucais e prejudicar as reações teciduais frente a injúrias, o que pode ser preocupante durante um tratamento odontológico, principalmente cirúrgico mas também em situações de reabilitação oral ou em tratamentos odontológicos de rotina. / Obesity in childhood has becoming a concern. Obesityy is associated with increased triglycerides, decreased high-density lipoprotein cholesterol levels, and increased low-density lipoprotein cholesterol and may lead to increased risk for hypercholesterolemia and cardiovascular complications in adult life. Clinical symptoms and signs of elevated cholesterol levels do not occur until adulthood, but subclinical aspects may be observed in children and adoslecentes. There are no studies on the effects of hypercholesterolemia in children, adolescents or in adults on oral tissues. We propose to study the influence of early age hypercolesterolemia in epithelial oral tissues and on wound healing. Male albino Wistar rats (40g) received enriched cholesterol diet (1%) for 2 and six weeks for epithelial evaluation. After 2 weeks, one control group (receiving standard pellet diet) and treated (hypercholesterolemic diet) received surgical wounds at the dorsum. Animals were sacrifed 1, 3 and 7 days after surgery. At the end of both periods (2 and 6 weeks) animals were sacrificed for epithelial evaluation. At the sacrifice time, serum were collected for evaluation of triglycerides, total cholesterol, HDL, LDL and VLDL. Were collected skin, tongue, palate and gingival tissues. Skin samples were also used for evaluation of the wound healing. All the observation were made at light microscopy. Data were statistically analysed by Mann Whitney U test for comparison between two samples. P[U] &le;0.05 were considered statistically significant. The enriched cholesterol diet significantly increased the total cholesterol, triglycerides, LDL and VLDL plasma content, and the study provide support for the hypothesis that hypercholesterolemia may be associated with deficiencies in the wound healing process. An important clinical implication of this study is the identification of alterations epithelium on oral tissues and in early phases of wound healing associated with subclinical but important alterations in cholesterol levels.

Esta dissertação investiga o comportamento linguístico de crianças brasileiras entre 4;0 e 6;11 anos de idade, acerca da produção de orações relativas de objeto direto e de objeto preposicionado. Segundo Friedmann, Belletti e Rizzi (2009), essa dificuldade existe devido ao traço [+NP] presente no sujeito da relativa e no núcleo relativizado. Para os autores, a gramática infantil computa o sujeito da relativa como um elemento interveniente que impede a relativização do objeto, resultando em uma violação semelhante à Minimalidade Relativizada (Rizzi, 1990). Por outro lado, estudos experimentais como o de Gennari e Macdonald (2008) indicam que essa dificuldade está ausente em relativas de objeto contendo um sujeito animado e um núcleo relativizado inanimado. Partindo desses estudos, desenvolvemos uma tarefa de produção eliciada com pares de figuras. Em nossos materiais, controlamos o traço de animacidade do sujeito da relativa e do núcleo relativizado, de modo a observar quais configurações de animacidade resultam em uma maior dificuldade para as relativas de objeto. Nossos resultados sugerem que as relativas de objeto direto mais difíceis contêm um sujeito inanimado. Isto ocorre uma vez que esta posição sintática é comumente preenchida por um argumento animado (Becker, 2014). O frequente uso de estratégias de esquiva nessas relativas indica que animacidade possui um papel determinante para facilitar ou dificultar a produção de relativas de objeto direto. No que diz respeito às relativas de objeto preposicionado, nossos resultados indicam que todas as configurações do traço de animacidade foram difíceis para nossos sujeitos de pesquisa, não sendo determinante a configuração de animacidade nessas relativas. Sugerimos que um conjunto de fatores pode estar envolvido para a dificuldade observada nessas construções: a ausência de relativas com pied-piping preposicional na fala dos adultos; a maior simplicidade derivacional em relativas preposicionadas com um resumptivo nulo ou pronunciado (Roeper (2003); Lessa de Oliveira (2008)); as relativas com pied-piping preposicional dependem de seu ensino formal (Corrêa (1998); Guasti e Cardinaletti (2003)). / This dissertation investigates the linguistic behavior of Brazilian children aged between 4;0 and 6;11, in relation to the production of direct object and prepositional object relative clauses. According to Friedmann, Belletti and Rizzi (2009), such difficulty arises due to the [+NP] feature present in the relative clause subject and the relativized head. To the authors, the child grammar takes the relative subject as an intervening element that hampers the relativization of the object, resulting in a violation resembling Relativized Minimality (Rizzi, 1990). On the other hand, experimental studies like Gennari and Macdonald (2008) indicate that such difficulty is absent in object relatives featuring an animate subject and an inanimate relativized head. Based on these studies, we designed an elicited production task with pairs of pictures. In our experimental material, we controlled the animacy feature in both the relative subject and the relativized head, so as to check which animacy configurations render the object relatives more difficult. Our results suggest that direct object relatives become more difficult when they feature an inanimate subject. That happens because the subject position is typically filled by an animate argument (Becker, 2014). The frequent use of avoidance strategies in these relatives indicates that animacy plays a determining role in facilitating or hindering the production of direct object relatives. Regarding the prepositional object relatives, our results indicate that all the animacy configurations were difficult for our research subjects, so that animacy does not play a determining role in the production of these relatives. We suggest that a number of things might be involved in the difficulty observed in these constructions: the absence of relatives featuring prepositional pied-piping in the speech of adults; the bigger derivational simplicity in prepositional relatives with a null or a pronounced resumptive (Roeper (2003); Lessa de Oliveira (2008)); relatives featuring prepositional pied-piping require formal learning (Corrêa (1998); Guasti e Cardinaletti (2003)).