52 research outputs found

    Production of biodiesel from palm oil

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    The present researches study the alternative fuel to replace the diesel fuel and how to produce the alternative fuel. Diesel fuel which is made from fossil fuel due the anaerobic decomposition through million years cause many harmful effect to the environment and human health such as the greenhouse effect, air pollution, acidification and more. The aim of the study is to produce the biodiesel from vegetable oil which is palm oil. It starts with mixing the 50 ml of ethanol and 0.5 g of sodium hydroxide as catalyst. The dissolved catalyst then will be poured into the heated 250 ml of palm oil and be stirred for 30 minutes. After the content is mixed the transesterification method is carried out. The content then transferred to separating funnel for separating process. At the end, two layers which the bottom layer will be by- product and the upper layer will be biodiesel. The biodiesel will enter purification method which rinse it with hot distilled water and ready to be test which are the density, kinematic viscosity and heating value of the biodiesel. By using biodiesel as an alternative fuel, the environment and human health will be secure more and it may attract people to more concern about the benefits of the biodiesel

    The biomechanical optimisation (tuning) of the Ankle Foot Orthosis-Footwear Combination (AFO-FC) of children with cerebral palsy : the effects on sagittal gait characteristics, muscle and joint characteristics and quality of life

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    The current study aimed to investigate influences of rigid Ankle Foot Orthoses (AFOs) on gait in children with Cerebral Palsy (CP), immediate effects of tuning of AFO-FC (AFO-Footwear Combination) on gait of children with CP, short-term effects of tuning of AFO-FC on gait, muscle and joint characteristics and quality of life in children with CP, and the feasibility of conducting a larger trial. The study included 11 healthy children and 8 children with CP. Outcome measurements included sagittal plane kinematics and kinetics derived using 3D motion analysis, Gait Deviation Index (GDI), physical examination, and quality of life using the PedsQL™ questionnaire. Data from healthy children demonstrated influences of shoes on gait parameters and the role of the ankle joint in adapting to various wedges and rockers during gait. When studying children with CP, beneficial effects of rigid AFO-FC on gait parameters were evident; these were thought to relate to the appropriateness of the AFO-FC and familiarisation with the prescription. Immediate effects of tuning varied according to gait patterns previously demonstrated with non-tuned AFO-FC; benefits to knee kinematics and kinetics were largely seen in legs with extended knee gait, followed by jump knee gait, and with poorest responses in legs with crouch knee gait. Short-term effects of tuning were evident when comparing measurements taken before and after two-to-four months of wearing the tuned AFO-FC. Barefoot walking demonstrated significantly improved walking speed. Stride-length improved when comparing tuned AFO-FC at baseline with the tuned AFO-FC following the intervention period. No short-term changes were seen in PedsQL™ scores, muscle and joint characteristics, and GDI. Feasibility issues were also identified. It was concluded from this exploratory trial that tuning of AFO-FC improved gait for children with CP, although initial gait pattern affected the amount of benefit. This was evident immediately after tuning and some parameters improved further after short-term intervention. A randomised controlled trial is required; power analysis indicates the need for a larger sample of 18 in each group to detect change in GDI with a medium effect size and at a power of 0.8 and p <0.05.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

    A Loosely-Coupled Passive Dynamics and Finite Element based Model for Minimising Biomechanically Driven Unhealthy Joint Loads during Walking in Transtibial Amputees

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    The primary objective of a prosthetic foot is to improve the quality of life for amputees by enabling them to walk in a similar way to healthy individuals. Amputees su˙er from health risks including joint pain, back pain and joint inflammation. The aim of this thesis is to develop a new computational approach to reduce the likelihood of biomechanically driven joint pain in transtibial amputees resulting from sustained exposure to Unhealthy Loads (ULs) during walking. This is achieved by developing a computational methodology to achieve a customisable sti˙ness design solution for prosthetic feet so that the occurrence of unhealthy joint loads during walking is minimised.It is assumed that the healthy population is able to spend energy most optimally during walking at all walking speeds. During walking, the force exerted by the body on the ground is measured by the ground reaction force (GRF). The GRF value is normalised with the body weight defining a dimensionless parameter . The values are similar for both legs in healthy populations but are di˙erent for the sound and a˙ected leg for amputees. A new hypothesis has been proposed in this thesis that walking is comfortable for an amputee when the di˙erence between values is minimal between the amputee and an equivalent healthy population. The values for healthy adults, as well as amputees, follow a finite number of patterns. The pattern of the values (or the GRF curve) depends on the walking speed of an individual, categorised as slow, fast or free walking. However, it is observed in the literature that free walking speed (FWS) varies over a wide range for healthy individuals (e.g. 1.1 m/s to 1.5 m/s). As a result, it was diÿcult to establish a relationship between walking speed and GRF pattern. A novel parametrised description of GRF curves for a healthy population and amputees is proposed so that a new dimensionless velocity ratio parameter and the corresponding value of the FWS can be predicted by observing the GRF pattern of a healthy adult or an amputee. A new classification approach based on the parametrised description of GRF curves, along with the dimensionless velocity ratio parameter, has been recommended for categorising very slow, slow, free, fast and very fast walking. The GRF result predictions are validated on healthy adults in an experiment conducted in a gait lab. A group of candidates who walk a lot in their daily life were specially selected for this experiment. This classification approach is used to develop a new measure of ULs based on the parametrised GRF description for healthy population and amputees. An innovative computational methodology is proposed to design an optimal sti˙ness response of a prosthetic foot that minimises the occurrence of ULs. This is achieved by transferring the roll-over shape (ROS) information of the prosthetic foot and the corresponding information for a given velocity ratio across a passive walking dynamic (PWD) and a finite element model via a newly defined form of loose coupling. A theoretical case study is presented in which an amputee walks in a gait lab with a representative C-shaped prosthetic foot. The thesis explains how the proposed novel computational methodology is able to redesign the prosthetic foot in a way that is better suited to minimising ULs. The redesign process of the prosthetic foot has led to the development of an innovative 3D printable double keel and double heel design. With the advancement of carbon reinforced polymers and additive manufacturing technology, the sti˙ness customisation methodology proposed in this thesis has the potential to create a new generation of energy-eÿcient prosthetic feet

    Systems for Noninvasive Assessment of Biomechanical Load in the Lower Limb

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    Every move you make—and, yes, every step you take—is the result of action at a joint, and so proper joint function is pivotal to the way we explore and interact with the world around us. Unfortunately, joint function is often disrupted by injuries, chronic disorders, or neurological deficits, which can, in turn, disrupt quality of life. Many forms of joint dysfunction derive from adverse biomechanical loading conditions—that is, the forces and torques to which our limbs are subjected—and, thus, techniques for monitoring these loads during daily life may improve our understanding of how injuries and disorders arise and progress—and, most importantly, how best to treat them. The standard methods for assessing these loading conditions, however, are almost all benchtop-bound and confined to laboratories or clinics, so their utility in at-home or ambulatory settings—where they may be most impactful—is limited. In an attempt to address this void, in this work, we present three novel techniques for extracting information related to joint loading using a synthesis of noninvasive / wearable sensing and machine learning. First, we detail the development of an adjustable-stiffness ankle exoskeleton with multimodal sensing capabilities and use it to explore how humans interact with external elastic loading of the ankle during walking. Then, in an attempt to peer “under the skin,” we develop a novel form-factor for capturing joint sounds— the skin-surface vibrations produced by articulating structures internal to the joint—and demonstrate that these noninvasive measurements can be used to discriminate levels of axial loading at the knee. Finally, taking the concept of joint acoustics one step further, we introduce a new, active acoustics-based technique whereby the tensile loading of a particular tissue—the Achilles tendon—can be estimated by measuring the tissue’s mechanical response to a burst vibration on the skin surface. Using this approach, we are able to assess this loading state (and, by association, the net moment at the ankle) reliably across several activities of daily life, and, through a proof-of-concept study, we demonstrate how the technique can effectively translate to a fully wearable device. Collectively, the efforts reported in this thesis represent a novel, multi-path approach to assessing biomechanical loading states in the lower limb and the effects thereof. These tools and insights may serve as a basis for future development of wearable, accessible technologies for monitoring joint load during daily life, thereby reducing injury risk, tracking disease progress, assessing the efficacy of treatment, and accelerating recovery.Ph.D

    Cognitive-motor interference in people with multiple sclerosis: a kinematic approach to clarify the effect of cognitive load on walking performance

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    The simultaneous performance of cognitive tasks during locomotion (or cognitive-motor dual-task) is known to cause performance deficits in either one of, or both tasks. Furthermore, these performance decrements are exacerbated by the presence of motor impairments and cognitive dysfunctions characteristic of numerous neurological diseases, such as multiple sclerosis (MS). In this regard the assessment of walking while performing a cognitive task may represent a relevant outcome measure, because it allows measuring, in a laboratory setting, individual’s ability to cope with walking challenging situations similar to everyday living. The first aim of this thesis is to provide an experimental setup, based on the use of optoelectronic stereophotogrammetry, for obtaining quantitative evaluation of walking biomechanics and motor strategies during dual-task performance in both healthy adults and people with MS (pwMS). Then, this experimental methodology is tested as suitable method not only for detecting, measuring and characterizing disability, but also for testing intervention effectiveness in clinical practice. Specifically, the study is focused on the assessment of spatiotemporal parameters and lower limb kinematics during single- (normal pace walking) and dual-task (walking while performing a discrimination and decision-making). This thesis is composed of four experiments. The first two aimed to measure the effect of cognitive-motor interference on walking biomechanics in terms of spatiotemporal parameters and lower limb joint kinematics. In this regard, a sample of pwMS stratified by disability level (low disability, EDSS 1.0-2.5, n=37; mild to moderate disability, EDSS 3.0-6.0, n=44) and a sample of age- and gender-matched healthy adults (n=41) underwent a 3D kinematic evaluation of single- and dual-task performance using a motion capture system. Differences between conditions and groups were investigated using a two-way repeated ANOVA. The results reported that gait speed and stride length were sensitive motor variables in detecting differences from single- to dual-task condition in both pwMS and unaffected individuals, whereas spatiotemporal parameters closely related to balance control (e.g. step width, double support phase duration) were sensitive to changes only in pwMS with moderate disability. Moreover, those patients showed significant changes in the kinematics of distal joint (shank-foot) and proximal joint (hip), including a reduction in ankle plantarflexion and hip extension peak at the terminal stance phase. These observed changes in more impaired patients are compensatory mechanism to stabilize body posture and allow safe locomotion during complicate dual-task activities. Finally, the other two experiments were designed to provide a clinical application of this methodology, as a tool for quantitatively assessing biomechanics changes after an innovative therapeutic intervention. In this regard, a sample of pwMS (n=34) with mild to moderate disability participated in a bicentric clinical trial. As per protocol, pwMS completed an intervention consisting of either active or sham multiple sessions of transcranial direct current stimulation (tDCS) combined with physical activity, aimed to improve walking performance. Following repeated application of active tDCS, the results obtained from the quantitative gait analysis showed greater improvements in gait velocity, step length and walking endurance. This improvement measured in walking had corresponding effects on walking dual-task performance. In fact, the dual-task cost of gait parameters was significantly reduced after the active tDCS intervention. In conclusion, the quantitative assessment of walking impairments during the execution of functional task in pwMS can support a deep learning of both movement features and motor strategies, which should have implications for the design and validation of clinical intervention aimed at improving functional walking

    Robust pedestrian trajectory reconstruction from inertial sensor

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    International audienceIn this paper, a strides detection algorithm combined with a technique inspired by Zero Velocity Update (ZUPT) is proposed using inertial sensors worn on the ankle. This innovative approach based on a sensors alignment and machine learning can detect both normal walking strides and atypical strides such as small steps, side steps and backward walking that existing methods struggle to detect. As a consequence, the trajectory reconstruction achieves better performances in daily life contexts for example, where a lot of these kinds of strides are performed in narrow areas such as in a house. It is also robust in critical situations, when for example the wearer is sitting and moving the ankle or bicycling, while most algorithms in the literature would wrongly detect strides and produce error in the trajectory reconstruction by generating movements. Our algorithm is evaluated on more than 7800 strides from seven different subjects performing several activities. We validated the trajectory reconstruction during motion capture sessions by analyzing the stride length. Finally, we tested the algorithm in a challenging situation by plotting the computed trajectory on the building map of an 5 hours and 30 minutes office worker recording

    The effects of biomechanically optimised ankle-foot orthoses-footwear combinations on the gait of children with cerebral palsy

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    The purpose of this study was to investigate the effects of the biomechanical optimisation of ankle-foot orthoses and footwear combinations (AFO-FCs) on the gait and energy expenditure of children with cerebral palsy (CP). The child's perception and compliance of wearing AFO-FCs were also investigated. Additional aims were to examine common clinical practice regarding AFO-FC tuning in the UK and to study the validity of using the static shank to vertical angle (SVA) to measure the dynamic SVA during gait. The study included five children with CP. Outcome measurements included sagittal plane kinematics and kinetics derived using 3D motion analysis, physical examination, heart rate (HR), energy expenditure, speed, distance, energy expenditure index (EEI), static SVA and dynamic SVA and an after study questionnaire. When studying children with CP, beneficial effects of biomechanically optimised AFO-FCs on gait parameters were evident; the results identified improvements to knee, hip and pelvic kinematics, particularly in cases where the principal gait deviation was hyperextension of the knee in stance. There were also beneficial effects on energy expenditure with the study highlighting a reduction in energy expenditure, and an increase in self-selected speed and distance covered, when walking in a biomechanically optimised AFO-FC compared to a non-tuned AFO-FC. The study demonstrated validity in using the static measurement of the SVA to estimate the dynamic SVA during temporal mid-stance (TMST). The importance of cosmesis and social inclusion was also highlighted as being important for disabled children who are asked to wear adapted footwear and AFOs. However, the results of this study indicated that when there is an improvement in physical function and activities of daily living, children will choose to comply with what they perceive to be uncosmetic orthoses. It was concluded that biomechanically optimised AFO-FCs have the potential to improve the kinematics and kinetics of gait, energy expenditure, speed and distance covered for children with CP, and that tuning the AFO-FC should be mandatory
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