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Identifying potential risk factors that affect slip-induced falls is key to developing effective interventions for reduction of injuries caused by these accidents. Existing epidemiological evidence suggests that localized muscle fatigue might be considered as an intrinsic risk factor that causes lack of balance control leading to falls. The literature on the relationship between localized muscular fatigue of the lower extremity and the gait parameters affecting slip severity is scarce. The purpose of the present study was to examine how lower extremity fatigue (quadriceps) alters gait parameters and increases slip severity. Sixteen healthy young participants were recruited to walk across an unexpected slippery floor in two different sessions (Fatigue and No fatigue). Kinematic and kinetic data were collected using a three-dimensional video analysis system and force plates during both sessions. The gait parameters important in assessing slip severity were compared for the two different sessions to evaluate the effects of fatigue. A repeated measure one-way analysis of variance (ANOVA) and multivariate analysis was employed to predict statistical significance. The results indicated a substantial increase in the heel contact velocity (HCV), required coefficient of friction (RCOF), slip distance II (SDII), peak average knee joint moment during slip recovery (kneemompeak), fall frequency and, a decrease in the transitional acceleration of the whole body COM (TA) in the fatigue session further indicating higher slip severity due to fatigue. In addition, a strong positive correlation was observed between RCOF and HCV, HCV and SDII, and, SDII and kneemompeak. These findings provide new insights into the relationship between localized muscular fatigue and slip initiation/recovery process. The present study concluded that localized muscular fatigue affects the gait parameters and increases slip severity and hence can be considered as a potential risk factor for slip-induced falls. / Master of Science

Surface tension is an essential force for the functioning of the world and life. Centuries of study, and still, new applications and limits of surface tension are being explored. Water has always drawn attention for its high surface tension value, 72mN/m compared to ethanol's 20mN/m. The high surface tension allows for numerous applications, superhydrophobic surfaces being one that takes heavy advantage of that value. Superhydrophobicsurfaceshave a high surface energy cost with water, resulting in small contact areas with high advancing and receding contact angles and low contact angle hysteresis. This results in very low adhesion on the surfaces. Here we study the ability of superhydrophobic surfaces with their low adhesion to shed meltwater from frost, showing a decrease in frost thickness to below 3mm for the meltwater to shed. We then take another approach to removing water from a surface, rather than increasing the surface energy cost, we introduce a difference in surface energy cost. Introducing a porous surface across from a solid one, droplets transfer from the solid to the porous, removing over 90% of the volume of the droplet from the solid surface. We thoroughly examine and model the hydrodynamics of the transfer process, varying the solid surface, the donor surface, and the liquid. This bridging between surfaces is then applied to fog harps, examining the efficiencies of large-form fog harps. Fog harps have shown a 3 to 5 times increase in water collection compared to the industry-standard mesh collector. However, droplets from fog collected on the wires eventually grow large enough to touch neighboring wires. Tominimizetheirsurfaceenergy, they begin pulling wires together, "tangling" them. This can potentially reduce efficiency, but has not been applied to large-scale harps until here. Another application of surface tension is then examined, using lower surface tension oils, but trapping them in microstructures to make slippery liquid-infused porous surfaces (SLIPS). The oil coats the microstructure, due to its lower surface tension. This creates a lubricating layer on the surface, along with potential air pockets reducing friction further. These surfaces have been studied extensively with liquids being placed on them, but here we begin to examine them when solids are used instead, showing some interesting cases where increasing the viscosity of the oil actually decreases the friction force. / Doctor of Philosophy / Sponges are something everyone has used, and most people can tell you that they work using surface tension. And for most people, that's enough. It's actually more useful to know to squeeze your sponge dry when you're done to prevent mold than it is to know that it holds onto liquids because of surface tension. But the point here was to take the study of sponges and surface tension to the extreme. To the point that some knowledge is going to be gained solely for the sake of gaining knowledge. Not all knowledge will have immediate uses, but this doesn't take value away from the knowledge, or any eventual uses it might have. So we start this by looking at the building of scientific knowledge and noticing that a brick is missing. Superhydrophobic surfaces, surfaces that water doesn't want to touch, have been studied very extensively and their properties have been thoroughly explored. However, a direct comparison of the defrosting behaviors, the process of frost melting on a surface, between superhydrophobic and hydrophobic surfaces had not been done. Water does prefer to be on a hydrophobic surface compared to a superhydrophobic one, but it's still uncomfortable. A plate was treated so that half was hydrophobic and the other half was superhydrophobic. Frost was grown across the surface and then melted simultaneously, allowing us to characterize the differences in the behaviors, highlighting the ability of the superhydrophobic surface to shed water droplets at smaller sizes than other surfaces. Next is a pure fluid mechanics work supporting a heat transfer application. Evaporation, for enhanced heat transfer, and a hydrophilic wick, essentially a sponge, are paired to create a plate with one-way heat transfer. Heating side A can heat side B, but heating side B can't heat side A. Water in the wick gets heated, evaporates from side A and then condenses on side B, carrying heat with it. The condensation grows until it touches the wick, which then pulls it in, allowing it to be evaporated again and cycling more heat. When side B, the smooth surface, is heated, the water can evaporate off it and condense in the wick, but then it has no way to return, preventing further heat transfer. The process of droplets being pulled from side B to the wick in side A is key to the process. It's a sponge pulling water in using surface tension. However, all the smaller pieces have been taken for granted. The second piece is a systematic study of this capture mechanism, exploring the effects of changing liquids, donor surfaces, and receiving porous wicks. The third is a continuation of the lab's previous work on Fog Harps, arrays of vertical fibers held in place to let fog run into them. The droplets grow until they slide down and can be collected. The wires of the harp are close enough that the water can actually start to tangle them together. This tangling can increase the water needed for sliding and collection to begin. Tensioning the wires can help mitigate the tangling. Here we show harps on around 1,$text{m}^2$, using optimal wire size and spacing that is possible for mass manufacturing. The harps were tested in the lab using humidifiers to generate fog for the harps to collect. Finally, an initial study of solid objects being pulled across oil-infused microstructured surfaces. The microstructure helps keep the oil on the surface thanks to the surface energy of the oil. These oil-infused surfaces have been studied extensively when liquids are placed on them, but not with solid objects. Solid objects can exert significantly more pressure than liquids, which naturally want to spread when they reach a certain thickness. Experiments were performed with a variety of oil viscosities, microstructures, and oil excess thicknesses. This work is not entirely complete but a significant portion of it is presented here.

Falls are the leading cause of fatal and non-fatal injuries among older adults. Age-related sensory degradation may increase instability and increase the risk of slips and falls in older adults. The integration of three sensory systems (visual, proprioceptive, and vestibular systems) and the respective weighting of each are needed to maintaining balance during unexpected slip-induced falls. The visual system is often thought of as the most important sensory system in playing a major role in stabilizing posture, guiding locomotion and controlling slip response. However, previous studies have focused on the age-related effects of visual input on static postural stability. The age-related effects of visual input associated with locomotion and unexpected slip perturbations (i.e., dynamic tasks) remains unclear. The purpose of this study is to investigate the age-related effects of visual input on multi-sensory processing during locomotion and unexpected slip perturbations. Fifteen young and fifteen old adults were recruited to participate in this study. Motion capture system, force plate, and EMG data were collected during the experiments. Various biomechanical and neuromuscular characteristics were identified to quantify the age-related effects of visual input during locomotion and unexpected slip perturbations. The results indicate that temporary loss of visual input during walking could cause individuals to adopt a more cautious gait strategy to compensate for their physical and neuronal changes as shown in increased double support time and higher co-contraction (i.e., stiffness) of the knee and ankle joints. Older adults also have higher co-contraction at the ankle joint during walking as compared with young adults. Regarding slip-induced falls, temporary loss of visual input causes increased slip distances and response times of upper and lower limbs in both younger and older groups. In terms of kinematics, the combination of age and temporary loss of visual input influenced the perturbed limb. In terms of muscle activation patterns, temporary loss of visual input may increase the proprioceptive gain as shown in early muscle activity onset, increased muscle activation duration, and increased co-contraction at the knee joint. However, stiffness may increase the difficulty to detect a slip event and reduce flexibility and increase slip-induced falls. Although the human body cannot fully compensate for the temporary loss of visual input, the results in this study suggest that the reweighting process increases proprioceptive gain while visual input is unavailable. These findings support the implication of future research in order to understand the potential hazards which could occur while walking and slipping with temporary loss of visual input. The results may also contribute to the design of effective interventions to improve motor learning by applied visual occlusion in slips/falls training to reduce fall risk and enhance safety. The visual occlusion paradigm may assist to increase learning encoded in intrinsic coordination, related to motor performance skill, providing the flexibility required to adapt to complex environments such as slip-induced falls. / Ph. D.

Adults with mental retardation (MR) experience a greater number of falls than their non-disabled peers. To date, efforts to understand the causes for these falls have primarily involved qualitative studies that use largely subjective measures to quantify stability. Performing a more objective biomechanical gait analysis may better explain the reasons for these fall accidents and provide repeatable measures that can be used for comparison to determine the effectiveness of interventions intended to reduce slip-related falls. A gait analysis was conducted to quantify normal walking and slip response characteristics for adults with MR as well as a group of non-disabled age- and gender-matched peers. Kinetic and kinematic data were collected and a number of variables relating to gait pattern, slip propensity, and slip severity were calculated to compare the differences between groups. Results showed that adults with MR exhibit slower walking speeds, shorter step lengths, and greater knee flexion at heel contact suggesting that their gait patterns share more similarities with the elderly than with healthy adults of an equivalent age. Unexpectedly, the MR group demonstrated a lower required coefficient of friction (RCOF) and slower heel contact velocity which, alone, would suggest a reduced slip propensity as compared with the healthy group. A greater peak sliding heel velocity and greater slip distance measures, however, indicate greater slip severity for the MR group. The findings of this study suggest that falls in this population may be attributed to delayed response to slip perturbation as measured by slip distances. / Master of Science

The objective of the proposed study was to perform three-dimensional (3D) inverse dynamics analysis to determine lower extremity (ankle, knee and hip) joint moments on previously collected slip perturbation experimental data. In addition, the aging effect on the joint moment generation in both normal walking and reactive-recovery conditions was examined. Dataset collected during previous slip and fall experiments, which were conducted in a typical gait analysis setting, were analyzed in current study. All the participants were subjected to the screening criteria, which defined the successful reactive-recovery (i.e. non-fall trials) based on slip distance, sliding heel velocity, whole body COM velocity, and motion pictures. Nine young and nine old healthy participants, who were identified possessing representative trials, were involved as participants in current study. A local coordinate system was constructed on each joint and each segment of the lower extremity based on available landmarks using the Gram-Schmidt orthogonalization algorithm. 3D inverse dynamics was implemented to obtained lower extremity joint moments. Magnitude and timing of obtained joint moment patterns during stance phase were subjected to one and two-way analysis of covariance (ANCOVA) with walking velocity as covariate. The aging effect and gait condition effect were evaluated. Increases in peak joint moment, peak joint power, and joint moment generation ratio were detected in successful reactive-recovery. Distinct age-related joint moment generation strategy was observed through findings of peak joint moment ratio and joint moment generation rate. The elderly, who were able to reactive recover, were found to be as rapid as their younger counterparts in terms of initiating and developing reactive joint moment. It was concluded that ankle joint was critical in balance recovery while hip joint assumed the major responsibility of balance maintenance of upper body during successful reactive-recovery. Increased demand on muscle strength during balance recovery lead to the distinct joint moment generation strategy adopted by the elderly, and confirmed the necessity of lower extremity strength training. In addition, implementation of 3D joint moment analysis was justified in current study and was suggested in future slip and fall researches. / Master of Science

<p>Together with Attends in Aneby a thesis of 15 ECTS (credits) have been undertaken. The assignment was to develop a new incontinence product for single use. Users of the product value comfort, flexibility, softness, comfort and a discreet product. Users are for individuals with incontinence problems that usually receive the products via prescription. The product must also have an attractive price and good quality from the purchase / originator's perspective.</p><p>Currently there are two models that Attends supplies, which the project intends to develop, (Slips / Briefs and Pull On's). The first has a low price but also lower usability than the other. The products have a well-developed absorptive function and with respect to this, only a new design of the chassis will be developed. Project issue were: <em>How should a concept look like when combining Pull On's and Slips / Briefs? Is it possible to develop a better product?</em></p><p>Production methods, costs and customer satisfaction will not be taken into account given that incontinence is a sensitive topic and that it would make the task too extensive. Consideration of patents, industrial designs and design protection are not taken into account when over two hundred applications per month are registered.   The mission was carried out as a development project where the product is broken down into parts which are then developed and combined to form a new developed product. Tools that were used are brainstorming and morphological matrix. This project resulted in a concept that can be described as a hybrid of today's two products. With two parts of elastic material in the waist, the product will gain a better fit for the user. It also creates a wider span between the maximum and minimum waistline each size will cover. The final product also has an adjustment function to increase the user friendliness and comfort. With the help of adjustment so you can change the pressure against the body, making the user able to customize the product. A continuation of the project is to examine whether new materials can be inserted into the device instead of the elastic composite. It is important that further development of the product is made together with a test group to gain answers about ease of use and other problems that can arise in everyday use. A continuation should also involve interviewing healthcare professionals who come into contact with the product.</p>

Os lapsos de fala são enunciados que apresentam um desvio em relação ao que o falante pretendia dizer (cf. FROMKIN, 1973). Esse erro pode se manifestar em níveis linguísticos distintos, afetando segmentos fonológicos, morfemas, palavras ou sentenças. Muitos linguistas defendem que os lapsos de fala são uma importante evidência para a postulação de modelos de performance que levem em conta a realidade psicológica das unidades linguísticas e suas regras (cf. FROMKIN, 1973; PFAU, 2009; LEVELT, 1989). O objetivo do nosso trabalho é, portanto, investigar a estrutura dos lapsos de fala espontâneos do português brasileiro que afetam o nível morfológico e explicitar as propriedades que regem os lapsos na nossa língua. Para isso, adotamos como modelo teórico o sistema de Pfau (2009), que foi desenvolvido com base nas evidências fornecidas pelos lapsos de fala e tem como alicerces a arquitetura da gramática proposta no quadro teórico da Morfologia Distribuída (cf. HALLE; MARANTZ, 1993; MARANTZ, 1997) e o modelo de performance em níveis (cf. LEVELT, 1989). Nossa hipótese inicial é a de que o sistema proposto por Pfau (2009) consegue dar conta da análise dos lapsos de fala em português brasileiro. Os resultados da pesquisa incluem a construção de um corpus constituído por 140 dados, coletados pelo método naturalístico, isto é, os lapsos foram anotados em contexto natural e espontâneo de fala, sem indução por testes. Os dados apontam para a existência de diferentes estruturas subjacentes aos lapsos de fala morfológicos no português do Brasil, sendo possível classificá-los em seis tipos distintos de acordo com suas características. As classes são: (1) blends de palavra, (2) blends frasais, (3) substituições que envolvem aspectos semânticos, (4) substituições que envolvem aspectos fonológicos, (5) lapsos que envolvem morfemas, e (6) lapsos que atingem traços gramaticais. / The slips of the tongue are utterances that present a deviation as compared to the speaker\'s intention (cf. FROMKIN, 1973). This error can occur in different linguistic levels, affecting phonological segments, morphemes, words or sentences. Many linguists claim that the slips of the tongue constitute important evidence for proposing performance models that consider the psychological reality of the linguistic units and the rules that apply to them. Our aim is to investigate the properties of spontaneous slips of the tongue in Brazilian Portuguese and to determine the structure of those which affect the morphological level. Hence, we have adopted as a theoretical model the system proposed in Pfau (2009), which has been developed based on evidence from the slips of the tongue. This system takes as a starting point the architecture of the grammar proposed by the Distributed Morphology model for language treatment (cf. HALLE; MARANTZ, 1993; MARANTZ, 1997) and by a model based on performance levels (cf. LEVELT, 1989). Our initial hypothesis is that Pfau\'s system can manage the analysis for slips of the tongue in Brazilian Portuguese. The results of this research include a corpus formed by 140 data, collected according to a naturalistic method, noted under natural context and spontaneous speech, without any induction by test. The data point to the existence of different subjacent structures to the morphological slips of the tongue in Brazilian Portuguese, classified in six distinct categories according to their characteristics. These types can be described as: (1) word blends, (2) phrasal blends (3) substitutions based on semantic aspects, (4) substitutions based on phonological aspects, (5) slips involving morphemes and, (6) slips involving grammatical features.

Os lapsos de fala são enunciados que apresentam um desvio em relação ao que o falante pretendia dizer (cf. FROMKIN, 1973). Esse erro pode se manifestar em níveis linguísticos distintos, afetando segmentos fonológicos, morfemas, palavras ou sentenças. Muitos linguistas defendem que os lapsos de fala são uma importante evidência para a postulação de modelos de performance que levem em conta a realidade psicológica das unidades linguísticas e suas regras (cf. FROMKIN, 1973; PFAU, 2009; LEVELT, 1989). O objetivo do nosso trabalho é, portanto, investigar a estrutura dos lapsos de fala espontâneos do português brasileiro que afetam o nível morfológico e explicitar as propriedades que regem os lapsos na nossa língua. Para isso, adotamos como modelo teórico o sistema de Pfau (2009), que foi desenvolvido com base nas evidências fornecidas pelos lapsos de fala e tem como alicerces a arquitetura da gramática proposta no quadro teórico da Morfologia Distribuída (cf. HALLE; MARANTZ, 1993; MARANTZ, 1997) e o modelo de performance em níveis (cf. LEVELT, 1989). Nossa hipótese inicial é a de que o sistema proposto por Pfau (2009) consegue dar conta da análise dos lapsos de fala em português brasileiro. Os resultados da pesquisa incluem a construção de um corpus constituído por 140 dados, coletados pelo método naturalístico, isto é, os lapsos foram anotados em contexto natural e espontâneo de fala, sem indução por testes. Os dados apontam para a existência de diferentes estruturas subjacentes aos lapsos de fala morfológicos no português do Brasil, sendo possível classificá-los em seis tipos distintos de acordo com suas características. As classes são: (1) blends de palavra, (2) blends frasais, (3) substituições que envolvem aspectos semânticos, (4) substituições que envolvem aspectos fonológicos, (5) lapsos que envolvem morfemas, e (6) lapsos que atingem traços gramaticais. / The slips of the tongue are utterances that present a deviation as compared to the speaker\'s intention (cf. FROMKIN, 1973). This error can occur in different linguistic levels, affecting phonological segments, morphemes, words or sentences. Many linguists claim that the slips of the tongue constitute important evidence for proposing performance models that consider the psychological reality of the linguistic units and the rules that apply to them. Our aim is to investigate the properties of spontaneous slips of the tongue in Brazilian Portuguese and to determine the structure of those which affect the morphological level. Hence, we have adopted as a theoretical model the system proposed in Pfau (2009), which has been developed based on evidence from the slips of the tongue. This system takes as a starting point the architecture of the grammar proposed by the Distributed Morphology model for language treatment (cf. HALLE; MARANTZ, 1993; MARANTZ, 1997) and by a model based on performance levels (cf. LEVELT, 1989). Our initial hypothesis is that Pfau\'s system can manage the analysis for slips of the tongue in Brazilian Portuguese. The results of this research include a corpus formed by 140 data, collected according to a naturalistic method, noted under natural context and spontaneous speech, without any induction by test. The data point to the existence of different subjacent structures to the morphological slips of the tongue in Brazilian Portuguese, classified in six distinct categories according to their characteristics. These types can be described as: (1) word blends, (2) phrasal blends (3) substitutions based on semantic aspects, (4) substitutions based on phonological aspects, (5) slips involving morphemes and, (6) slips involving grammatical features.

Together with Attends in Aneby a thesis of 15 ECTS (credits) have been undertaken. The assignment was to develop a new incontinence product for single use. Users of the product value comfort, flexibility, softness, comfort and a discreet product. Users are for individuals with incontinence problems that usually receive the products via prescription. The product must also have an attractive price and good quality from the purchase / originator's perspective. Currently there are two models that Attends supplies, which the project intends to develop, (Slips / Briefs and Pull On's). The first has a low price but also lower usability than the other. The products have a well-developed absorptive function and with respect to this, only a new design of the chassis will be developed. Project issue were: How should a concept look like when combining Pull On's and Slips / Briefs? Is it possible to develop a better product? Production methods, costs and customer satisfaction will not be taken into account given that incontinence is a sensitive topic and that it would make the task too extensive. Consideration of patents, industrial designs and design protection are not taken into account when over two hundred applications per month are registered.   The mission was carried out as a development project where the product is broken down into parts which are then developed and combined to form a new developed product. Tools that were used are brainstorming and morphological matrix. This project resulted in a concept that can be described as a hybrid of today's two products. With two parts of elastic material in the waist, the product will gain a better fit for the user. It also creates a wider span between the maximum and minimum waistline each size will cover. The final product also has an adjustment function to increase the user friendliness and comfort. With the help of adjustment so you can change the pressure against the body, making the user able to customize the product. A continuation of the project is to examine whether new materials can be inserted into the device instead of the elastic composite. It is important that further development of the product is made together with a test group to gain answers about ease of use and other problems that can arise in everyday use. A continuation should also involve interviewing healthcare professionals who come into contact with the product.