41 research outputs found
Eyewitness: Platform Design for Visualizing and Synthesizing Media Video Content of Political Significance
No full textThis paper explores the conventions and limitations of the photographic medium, both material and representational. Suggesting that photography is situated at an important point within its evolution, the paper searches for new directions within a photo-based practice, which continues to challenge and push the limits of the medium. Examining the way in which photography mediates and shapes experience, this thesis engages with popular photography, as a language with its own syntactical and semantic rules. Through explorations of the syntax of photography, parallels are drawn between the structure of language and the structure of photography. Metonymic structures within photographic language are discussed, with examples of the artist's work that aim to reveal and disrupt the metonymic nature of images. The role of collecting in the practice is defined as a first step in a process of coming to understand the world and its representations. Asserting the power of collage to disrupt and challenge representations, through a process of play and embracing ambiguity and uncertainty, the thesis culminates with a discussion of the development of genre mixing within the practice as a necessary evolution
Development of a virtual reality milling machine for knowledge learning and skill training
Get PDFCurrent methods of training personnel on high cost machine tools involve the use of both classroom and hands on practical training. The practical training required the operation of costly equipment and the trainee has to be under close personnel supervision. The main aim of this project is to reduce the amount of practical training and its inherent cost, time, danger, personal injury risk and material requirements by utilising a virtual reality technology.
In this study, an investigation into the use of Virtual reality for training operators and students to use the Milling Machine was carried out. The investigation has been divided into two sections: first the development of Milling Machine in the 3D virtual environment, where the real machine was re-constructed in the virtual space.
This has been carried out by creating objects and assembling them together. The complete Milling machine was then properly modelled and rendered so it could be viewed from all viewpoints.
The second section was to add motion to the virtual world. The machine was made of functions as for the real machine. This was achieved by attaching Superscape Control Language (SCL) to the objects. The developed Milling machine allows the users to choose the material, speed and feed rate. Upon activation, the virtual machine will be simulated to carry out the machining process and instantaneous data on the machined part can be generated.
The results were satisfactory, the Milling Machine was modelled successfully and the machine was able to perform according to task set. Using the developed Virtual Model, the ability for training students and operators to use the Milling Machine has been achieved
Buckling and crushing behavior of foam-core hybrid composite sandwich columns under quasi-static edgewise compression
Get PDFBuckling and crushing behavior of foam-core hybrid composite sandwich columns under edgewise compressive load is dealt in this study. Composite laminates with different stacking sequence configurations made of glass and Dyneema-woven fabrics and AL 2024-T3 sheets were used in combination of polyvinyl chloride foam core to manufacture the specimens. Effects of face sheet thickness and stacking sequence configuration, slenderness ratio, boundary conditions, and sandwich reinforcement with through-thickness resin pins on the buckling and crushing behavior of the specimens were investigated. The results revealed that using the resin pins changes the unstable Euler buckling mode to a more stable progressive end-crushing and significantly increases the buckling load, specific buckling load, and energy absorption capability, which are highly favorable. Also, the results showed that in the specimens with fiber metal laminates, the major failure modes are face sheet-core debonding and face sheet delamination. However, based on the results, specimen with hybrid face sheets made from Dyneema fabrics and aluminum plates has the highest buckling load as well as the highest specific buckling load. Also, a specific fixture was designed to laterally clamp the sandwich column which causes a reduction in the probability of specimen end-crushing and significantly increases the buckling load. - The Author(s) 2019.The publication of this article was funded by the Qatar National Library.Scopu
Alizarin red S dye removal from contaminated water on calcined [Mg/Al, Zn/Al and MgZn/Al]-LDH
No full textAuthor's personal copy Mechanism of the neuroprotective role of coenzyme Q10 with or without L-dopa in rotenone-induced parkinsonism Author's personal copy
No full texta b s t r a c t Current treatment options for parkinsonism as a neurodegenerative disease are limited and still mainly symptomatic and lack significant disease-modifying effect. Understanding its molecular pathology and finding the cause of dopaminergic cell loss will lead to exploring therapies that could prevent and cure the disease. Mitochondrial dysfunction was found to stimulate releasing of reactive oxygen species (ROS) with subsequent induction of apoptotic neuronal cell death. The aim of the present study was to throw the light on the role of coenzyme Q10 with or without L-dopa in an experimental model of parkinsonism induced by rotenone in rats. The present work showed that rotenone (2.5 mg/kg/day i.p. for 60 days) induced a model of parkinsonism (group II) resembling the basic findings in human characterized by bradykinesia and rigidity manifested as an increase in catalepsy score (detected after 20 days with bad prognosis after 60 days) with marked decrease in striatal dopamine levels. This model confirmed the implication of mitochondrial-apoptotic pathway in the pathogenesis of parkinsonism as there was a decrease in levels of striatal complex I activity and ATP as well as extreme overexpression of the antiapoptotic protein Bcl-2, and also exhibited the role of coenzyme Q10 where its plasma and striatal levels were found to be decreased in comparison to the normal control rats (group I). This proposed pathogenesis was evidenced by the significant correlation between catalepsy score and the neurochemical parameters obtained in the current work. The treated groups started to receive the drug(s) after 20 days from induction of parkinsonism and continued to complete for 60 days. Oral administration of Co Q10 in a low dose 200 mg/kg/day (group III) or a high dose 600 mg/kg/day (group IV), resulted in amelioration of the mitochondrial induced apoptosis by dose-dependent restoration of striatal complex I activity, ATP levels with temperate increase in expression of Bcl-2 as well as decrease in catalepsy score. Although both low and high doses of Co Q10 resulted in significant increase in its plasma and striatal levels, but only the high dose was shown to reach the recommended therapeutic levels. As a current replacement therapy, oral administration of levodopa 10 mg/kg/day (group V), caused symptomatic improvement in the form of reduction of catalepsy score with restoration of striatal dopamine levels, but it did not show any significant effects on either striatal complex I activity, ATP levels or the expression of Bcl-2, pointing to the lack of its disease-modifying role. On the other hand, its administration with high dose of coenzyme Q10 caused the most marked symptomatic improvement in catalepsy score when compared to its administration with low dose of coenzyme Q10, or when compared to either coenzyme Q10 high dose or L-dopa, respectively. Moreover, administration of high dose coenzyme Q10 with L-dopa provided a significant increase in striatal complex I activity, ATP levels and Bcl-2 expression in comparison to group administered coenzyme Q10 low dose with L-dopa, in addition to the significant restoration of striatal dopamine levels and both plasma and striatal Co Q10 levels. Regarding that L-dopa is viewed as a replacement therapy in parkinsonism, it could be concluded that addition of coenzyme Q10 in a high dose in early parkinson's disease could be recommended based on its proved diseasemodifying role on several levels of the proposed mechanisms, including improvement of respiratory chain activity and intervention with neuronal apoptosis. A further research to investigate other apoptosis-targeted compounds will open a new era in the treatment of parkinsonism
Risk-Based Decision Support Model for Planning Emergency Response for Hazardous Materials Road Accidents
No full textI hereby declare that I am the sole author of this thesis. This is a true copy of the thesis, including any required final revisions, as accepted by my examiners. I understand that my thesis may be made electronically available to the public. ii Hazardous Materials (HazMat) are transported throughout Canada in a great number of road shipments. The transportation of HazMat poses special risks for neighboring population and environment. While HazMat accidents are rare events, they could be catastrophic in nature and could result in substantial damage to nearby communities. Effective emergency response plays an important role in the safe transportation of HazMat. Transportation of HazMat involves different parties, including shippers, regulators, and surrounding communities. While the shipping party is responsible for safe delivery of HazMat shipments, it is the responsibility of local emergency service agencies to respond to accidents occurring within their jurisdictions. In this research, th
Reperforming Minimally Invasive Microdiscectomy Approaches for Recurrent Lumbar Intervertebral Disc Prolapse
No full textBackground Data: Reperforming minimally invasive discectomy (MID) approaches are typically challenging and demanding for patients with recurrent lumbar disc herniation (rLDH).
Purpose: The aim of this study to assess the safety and efficacy of reperforming Minimally invasive discectomy in recurrent lumbar disc herniation surgery.
Study Design: Retrospective clinical case study.
Patients and Methods: The author reviewed the medical records all patients re-operated after MID during the period from June 2010 to April 2016 via minimally invasive approaches for recurrent lumbar disc herniation. Age, gender, presenting symptoms, disc herniation level and side, type of MID approach used in first surgery, period between 1st and 2nd surgeries, redo surgery duration, intra or post-operative complications, visual analogue scale VAS for pain at 1, 30, and 90 days postoperatively were recorded.
Results: We could track 18 patients (12 males, 6 females), with mean age 43.2±6.3 years. The most operated level was L4/5 in 12 patients. Disc herniation on the left side was presented in 11 patients. Mean duration between the two surgeries was 44±19 weeks. Main clinical presentations were recurrent leg pain in 16 patients and new onset of partial foot drop in 2 patients. Duration of redo surgery was 97±37 minutes. Intraoperative minor dural tears were reported in 2 with no serious sequels. VAS for leg pain improved from 7.3±1.2 preoperatively to 2.1±1.1, 1.4±0.5 and 1.2±0.4 at 1, 30 and 90 postoperative days respectively.
Conclusion: MID approach for rLDH following initial MID surgery sounds feasible option with better perioperative and short-term outcome. Clinical outcome in the present study showed favourable outcome regarding operative time and incidence of dural tears with CSF leak comparing to open approaches. (2017ESJ151
Multiple motor-unit muscle models for the design of FES systems
Get PDFMany functional electrical stimulation (FES) controllers have been developed using a simulation approach, the performance of these controllers depends on the muscle model accuracy. Realistic models of neuro-musculoskeletal systems can provide a safe and convenient environment for the design and evaluation of FES controllers. A typical FES system consists of FES controller, an electrical stimulator, electrodes and sensors.During FES, the stimulation level can change in a continuous fashion such that different motor-units are recruited at different muscle lengths and at different times. Furthermore, it is also not accurate to use the instantaneous length as input to the force-length relationship in dynamic (non-isometric) situations. Although instantaneous CE length is commonly used in FES control studies, empirical data from the literature were reviewed and it was concluded that the CE length at initial recruitment is a key parameter influencing total muscle force. The author presents a new multiple motor-unit Hill-type muscle model that accounts for different motor units being recruited at different CE lengths and different times. Hence the model can account for a continuously changing recruitment level whilst using the individual motor unit lengths at initial recruitment as input to the force-length relationship. Moreover, the model is capable of modelling fatigue and force enhancement & depression for the individual motor-units (i.e. the recruitment and time history effects). The model can also take account of the different force-length and force-velocity relationships for different fibre types by modelling these properties for the individual motor-units.The new multiple motor-unit model is described in detail, implemented and tested in Matlab. Open-loop simulation protocols are made on single/multiple motor-unit models using different CE lengths for the force-length relationship; on single/multiple motor-unit fatigue sub-models; and on single/ multiple motor-unit force enhancement & depression sub-models.A general model that can be used to represent all relevant models from the literature was developed. This model can also be used to build new models at different levels of complexity. Such a “General Model” could be used to study the effect of model complexity on FES controller design so that appropriate trade-offs between model complexity and accuracy could be determined. Results, limitations and possible future work are discussed
