<p>It is well known that transportation means high and varying loads for products as well as packages. To develop corrugated boxes with optimal design and efficient use of raw materials is crucial. Vibrations and shocks acting on pallets during transportation are transferred to the corrugated boxes and considerably reduce the integrity and life time of the boxes. The development of experimental and analytical tools for measurement and prediction of the influence of dynamic loads on the box performance, such as stacking strength and conservation of stacking pattern would therefore be of large practical importance. In order to develop such tools, it is important to know the load distribution between different boxes. This master thesis presents a technique for investigating these stresses based on a pressure sensitive film, which gives many data points. A series of tests using random and sinusoidal vibration testing have been done utilising this technique and results are presented for different positions on the pallet and for different box filling methods. Investigations performed on the vibrations of the boxes also demonstrate a pitch type of motion. A level-crossing study on the forces existing between the boxes shows a Rayleigh force distribution. A mathematical model is also proposed for simulation of a stacking system. Advantages and disadvantages with this technique and with the model are described. Comparison between the experimental and numerical results shows a proper correlation. Using the pressure sensitive film as a quantitative sensor and applying the recorded data for the statistical study of the contact forces existing in a stack of boxes gives useful and important results for further analysis of the fatigue life and vulnerable positions of boxes.</p><p> </p>

It is well known that transportation means high and varying loads for products as well as packages. To develop corrugated boxes with optimal design and efficient use of raw materials is crucial. Vibrations and shocks acting on pallets during transportation are transferred to the corrugated boxes and considerably reduce the integrity and life time of the boxes. The development of experimental and analytical tools for measurement and prediction of the influence of dynamic loads on the box performance, such as stacking strength and conservation of stacking pattern would therefore be of large practical importance. In order to develop such tools, it is important to know the load distribution between different boxes. This master thesis presents a technique for investigating these stresses based on a pressure sensitive film, which gives many data points. A series of tests using random and sinusoidal vibration testing have been done utilising this technique and results are presented for different positions on the pallet and for different box filling methods. Investigations performed on the vibrations of the boxes also demonstrate a pitch type of motion. A level-crossing study on the forces existing between the boxes shows a Rayleigh force distribution. A mathematical model is also proposed for simulation of a stacking system. Advantages and disadvantages with this technique and with the model are described. Comparison between the experimental and numerical results shows a proper correlation. Using the pressure sensitive film as a quantitative sensor and applying the recorded data for the statistical study of the contact forces existing in a stack of boxes gives useful and important results for further analysis of the fatigue life and vulnerable positions of boxes.

Made available in DSpace on 2016-06-02T20:19:14Z (GMT). No. of bitstreams: 1 3062.pdf: 2064067 bytes, checksum: 9736110404bad178c5bdecf3fbb8c52a (MD5) Previous issue date: 2010-02-14 / Financiadora de Estudos e Projetos / The gait initiation is set to transition from standing posture to the first step to reversing cyclical, and involves a motor program mediated by adjustments preparations necessary to propel the body forward (MELOUIN ET AL, 2000). Studies that approach the initialization mostly in the adult population have aimed to understand the limitations in postural disorders, aging and what little is in the child population also has a focus on disease and how this process occurs not because of the development of walking independent. This study aimed to describe how the gait initiation process occurs and how it changes as occurs the development of independent walking. We evaluated 29 subjects into three groups: G1 (15 months - 10 subjects), G2 (3 years - 9 subjects) and GA (Adult - 10 subjects). The variables were analyzed: amplitude of oscillation of the center of force toward the average side (COFML) and anterior posterior (COFAP) and average speed and VELAP VELML. The nonparametric Kruskal Wallis test was used to detect differences between groups; the significance level was p &#8804; 0.05%. Results of gait initiation: COFAP (cm) there was no statistically significant differences between groups. However, both groups showed significant differences in the COFML behavior (7.79cm = G1, G3 = 7.46cm, GA = 3.25cm, p = 0.01). Furthermore the variable VELAP (cm / s), showed no statistically significant difference between groups, as well as the variable VLML. Results of gait termination: variables results COFAP (G1 = 11.15 cm, G3 = GA = 8.69 cm and 5.17 cm) and COFML (G1 = 7.83 cm, G3 = 8 cm and 4.86 cm = GA) showed no statistically significant differences when purchased between the three groups proposed both as a platform to platform 2. VELAP (G1 = 4.13 cm / s, G3 = 3.16 cm / GA = 3.26 cm / s) and VELML (G1 = 9.74 cm / s, G3 = 5.72 cm / s and GA = 2, 49 cm / s) were not statistically different during the completion of the gait termination, the results indicated the importance that the strength center behavior and the ability to deal with the gravitational field during the gait initiation and how this process changes with the experience of walking independently. / A inicialização de marcha é definida como transição da postura em pé ao primeiro passo a marcha cíclica, e envolve um programa motor mediado por ajustes preparatórios necessários para propulsionar o corpo para frente (MELOUIN ET AL,2000). Os estudos que abordam a inicialização em sua maioria em população adulta têm como objetivo compreender as limitações posturais em patologias e no envelhecimento e o pouco que se encontra em população infantil também tem o foco em patologias e não como este processo ocorre em função do desenvolvimento do andar independente. Este estudo teve por objetivo descrever como ocorre o processo de inicialização da marcha e como este muda à medida que ocorre o desenvolvimento do andar independente. Foram avaliados 29 sujeitos em três grupos G1 ( 15 meses 10 sujeitos), G2 ( 3 anos 9 sujeitos) e GA (adulto 10 sujeitos). As variáveis analisadas foram: amplitude de oscilação do centro de força na direção médio lateral (COFML) e antero posterior (COFAP) e velocidade média VELAP e VELML. O teste não paramétrico de Kruskal Wallis foi utilizado para detectar diferenças entre os grupos, o nível de significância foi de p &#8804; 0,05%. Resultados Inicialização da marcha: COFAP (cm) não houve diferenças estatisticamente significativas entre os grupos. Porém, ambos os grupos apresentaram diferenças significativas para o comportamento da COFML (G1 = 7.79cm, G3 = 7.46cm, GA= 3.25cm e p= 0.01). Por outro lado a variável VELAP (cm/s), não apresentou diferença estatisticamente significativa entre os grupos,assim como a variável VLML. Resultados Finalização da marcha os resultados das variáveis COFAP (G1 = 11,15cm, G3 = 8,69 cm e GA = 5,17 cm) e COFML (G1 = 7,83cm , G3 = 8cm e GA = 4,86 cm) não apresentaram diferenças estatisticamente significativas quando compradas entre os três grupos propostos tanto para a plataforma 1 quanto para a plataforma 2. VELAP (G1 = 4,13cm/s, G3 = 3,16cm/s e GA = 3,26cm/s) e VELML(G1 = 9,74 cm/s, G3 = 5,72 cm/se e GA = 2,49 cm/s), não foram estatisticamente diferentes durante a finalização do marcha Como conclusão, os resultados indicaram importância que o comportamento do centro de força e a capacidade de lidar com o campo gravitacional durante a inicialização da marcha e como este processo muda de acordo com a experiência do andar independente.

Objectif: Suite aux traitements avec aligneurs, une insuffisance de contacts postérieurs est souvent notée cliniquement: existe-t-elle réellement, se corrige-t-elle spontanément? Cette étude vise à comparer la qualité de l’occlusion statique chez des patients ayant été traités avec boitiers conventionnels ou par aligneurs, dès la dépose des appareils orthodontiques et après six mois de mise en place fonctionnelle. Matériel and Méthodes: La mise en place fonctionnelle de l’occlusion chez des sujets traités par boitiers conventionnels (GB, n=25) ou par aligneurs (GA, n=14) et par a été évaluée par un système d’analyse occlusale informatisée (T-scan 9), au moment de la dépose (T0), puis à 3 et 6 mois de contention (T3 et T6). Les sujets (41% de filles, âge moyenne de 19,38 ± 5,98 ans), étaient traités sans extractions, ni chirurgie, avec pour contention des fils collés ou appareils sans recouvrement occlusal. La symétrie et la simultanéité des contacts ainsi que la position antéro-postérieure du centre de forces (CF) étaient évalués. Résultats : À tout moment (T0, T3, T6), aucune différence statistiquement significative n’a été observée quant à la position antéro-postérieure du CF (p=0,854), la répartition ou la simultanéité des contacts, quelle que soit la modalité de traitement. Le CF était situé antérieurement chez les patients de sexe féminin à tout temps (p=0,002). La mise en place fonctionnelle semblait être terminée dès trois mois pour les deux groupes. Conclusion: La qualité de l’occlusion était comparable dans les deux groupes six mois après la dépose des appareils orthodontiques, signifiant l’absence d’influence du type de traitement à court terme. Le sexe féminin pourrait être associé à un CF plus antérieur même après six mois de mise en place fonctionnelle. / Objective: Following aligner therapy, a lack of posterior contacts is common and is expected to resolve with settling. The aim of the study was to compare the quality of occlusion and settling, immediately after treatment and during a retention period of six months, in patients treated with fixed appliance therapy or clear aligners. Materials and Methods: 25 patients treated with fixed appliances and 14 patients treated with aligners were evaluated by a digital occlusal analysis (T-Scan 9) at time of debonding (T0) and 3 and 6 months later (T3 and T6). Subjects (41% female, average age 19.38 ± 5.98) were treated without extraction or maxillofacial surgery using either bonded wires or removable appliances without occlusal coverage as retainers. Contact symmetry, simultaneity and the antero-posterior position of the Center of Force (COF) were assessed at the time of debonding, and after 3 and 6 months of retention. Results: At all times of evaluation, the COF position was not statistically different for both treatment modalities (p=0.854), but was located more anteriorly in female patients when compared to male patients (p= 0.002). Settling appeared to be completed by 3 months in both groups. Conclusion: The quality of the occlusion was comparable after 6 months of settling when treated with either treatment modality indicating no short-term effect of treatment type. Females maintained a more anterior COF after six months of retention.