DYNAMIC MODELING AND OPEN-LOOP CONTROL OF A TWIN ROTOR MIMO SYSTEM

The Twin Rotor MIMO System is an aero-dynamical model of a helicopter with significant cross-couplings between longitudinal and lateral directional motions. In this project there are two main critical parts, which are the development of dynamic models for the characterization of 1-DOF horizontal and vertical part and also the design stage of the state-feedback controller to control the main and tail rotor of the TRMS. The dynamic models ofthemain andtailrotor of theTRMS were obtained by applying a step input to the rotors independently, one at a time. The step responses were then evaluated to find the relevantinformation and quantities to develop secondorder transfer function. From these linearized models, the state-feedback controllers were designed independently for the main and tail rotor by selecting desired pole locations and calculating the feedback gains. Real-time experiments were then performed using the feedback gains obtained to evaluate the performance ofthestatefeedback controllers designed. Strong interactions between the tail and main rotor also seen by performing 2-DOFreal-time experiments

DYNAMIC MODELING AND OPEN-LOOP CONTROL OF A TWIN ROTOR MIMO SYSTEM

The Twin Rotor MIMO System is an aero-dynamical model of a helicopter with significant cross-couplings between longitudinal and lateral directional motions. In this project there are two main critical parts, which are the development of dynamic models for the characterization of 1-DOF horizontal and vertical part and also the design stage of the state-feedback controller to control the main and tail rotor of the TRMS. The dynamic models ofthemain andtailrotor of theTRMS were obtained by applying a step input to the rotors independently, one at a time. The step responses were then evaluated to find the relevantinformation and quantities to develop secondorder transfer function. From these linearized models, the state-feedback controllers were designed independently for the main and tail rotor by selecting desired pole locations and calculating the feedback gains. Real-time experiments were then performed using the feedback gains obtained to evaluate the performance ofthestatefeedback controllers designed. Strong interactions between the tail and main rotor also seen by performing 2-DOFreal-time experiments

Multiple gastrointestinal melanoma causing small bowel intussusception

A 61-year-old gentleman presented with small bowel intussusception from small bowel melanoma intussusceptum. He complains of intermittent abdominal distension but no history of intestinal obstruction. Apart from this, he was also symptomatic anemia which required repeated transfusion for the past few months. The contrast-enhanced computed tomography of the abdomen shows an omental mass with small bowel intussusception. He then underwent an exploratory laparotomy with segmental resection of the affected segment. Histopathological examination confirmed primary gastrointestinal melanoma. Multiple small bowel malignant melanoma is a rare disease. It remains a controversial diagnosis as it may be a primary or metastasis from an unidentified or regressed primary cutaneous melanoma. Prompt surgical intervention enables us to obtain tissue diagnosis, prevent complete intestinal obstruction and strategize the goals of treatment for the patient

Performance of Waste Cooking Oil on Aged Asphalt Mixture

Asphaltic concrete pavement is popular worldwide, but this type of pavement requires frequent maintenance and rehabilitation as it cannot cope up with the increasing number of traffic vehicles and loads. Therefore, modifying asphalt pavement to reduce the damages and defects is necessary, thereby enhancing the serviceability of pavement. This study presents the effect of waste cooking oil on asphalt mixture at different ageing conditions. A 60/70 penetration-grade asphalt binder was used, and 5% of this binder was replaced with untreated and treated waste cooking oil. Asphalt mixtures were prepared at the selected 5% optimum bitumen content and under two tests, i.e. Marshall stability and resilient modulus. The findings showed the better stability and resilient modulus of long-term aged samples incorporated with treated waste cooking oil than the unaged and short-term aged samples. The incorporation of untreated waste cooking oil caused reduced performance compared with the controlled and long-term aged samples. This result can be attributed to the high acid value of waste cooking oil. Therefore, treated waste cooking oil can be used as a binder replacement given its significantly higher performance at the mentioned ageing condition than the controlled mixture.

Alteration in the functional organization of the default mode network following closed non-severe traumatic brain injury

The debilitating effect of traumatic brain injury (TBI) extends years after the initial injury and hampers the recovery process and quality of life. In this study, we explore the functional reorganization of the default mode network (DMN) of those affected with non-severe TBI. Traumatic brain injury (TBI) is a wide-spectrum disease that has heterogeneous effects on its victims and impacts everyday functioning. The functional disruption of the default mode network (DMN) after TBI has been established, but its link to causal effective connectivity remains to be explored. This study investigated the differences in the DMN between healthy participants and mild and moderate TBI, in terms of functional and effective connectivity using resting-state functional magnetic resonance imaging (fMRI). Nineteen non-severe TBI (mean age 30.84 ± 14.56) and twenty-two healthy (HC; mean age 27.23 ± 6.32) participants were recruited for this study. Resting-state fMRI data were obtained at the subacute phase (mean days 40.63 ± 10.14) and analyzed for functional activation and connectivity, independent component analysis, and effective connectivity within and between the DMN. Neuropsychological tests were also performed to assess the cognitive and memory domains. Compared to the HC, the TBI group exhibited lower activation in the thalamus, as well as significant functional hypoconnectivity between DMN and LN. Within the DMN nodes, decreased activations were detected in the left inferior parietal lobule, precuneus, and right superior frontal gyrus. Altered effective connectivities were also observed in the TBI group and were linked to the diminished activation in the left parietal region and precuneus. With regard to intra-DMN connectivity within the TBI group, positive correlations were found in verbal and visual memory with the language network, while a negative correlation was found in the cognitive domain with the visual network. Our results suggested that aberrant activities and functional connectivities within the DMN and with other RSNs were accompanied by the altered effective connectivities in the TBI group. These alterations were associated with impaired cognitive and memory domains in the TBI group, in particular within the language domain. These findings may provide insight for future TBI observational and interventional research

Stability and rutting resistance of porous asphalt mixture incorporating coconut shells and fibres

The influence of coconut shells (CS) and coconut fibres (CF) on the stability and rutting resistance of porous asphalt mixture is examined. Four different percentage replacement of CS and three different of CF as additives were investigate. CS and CF were put through chemical treatment by soaking them in 5wt% of Sodium Hydroxide (NaOH) solution before being involved in the mixture. Marshall Stability and asphalt pavement analyzer are performed to evaluate the Stability and rutting resistance of porous asphalt mixture. It was found that there appears to be an optimum CS replacement level of 10% and 0.3% CS during which the stability and rutting resistance increase significantly

Performance of Waste Cooking Oil on Aged Asphalt Mixture

Asphaltic concrete pavement is popular worldwide, but this type of pavement requires frequent maintenance and rehabilitation as it cannot cope up with the increasing number of traffic vehicles and loads. Therefore, modifying asphalt pavement to reduce the damages and defects is necessary, thereby enhancing the serviceability of pavement. This study presents the effect of waste cooking oil on asphalt mixture at different ageing conditions. A 60/70 penetration-grade asphalt binder was used, and 5% of this binder was replaced with untreated and treated waste cooking oil. Asphalt mixtures were prepared at the selected 5% optimum bitumen content and under two tests, i.e. Marshall stability and resilient modulus. The findings showed the better stability and resilient modulus of long-term aged samples incorporated with treated waste cooking oil than the unaged and short-term aged samples. The incorporation of untreated waste cooking oil caused reduced performance compared with the controlled and long-term aged samples. This result can be attributed to the high acid value of waste cooking oil. Therefore, treated waste cooking oil can be used as a binder replacement given its significantly higher performance at the mentioned ageing condition than the controlled mixture

Stiffness Modulus of Asphaltic Concrete Incorporating Coir Fibre and Subjected to Aging

The aim of this paper is to investigate the performance response of a set of coir fibre modified asphalt samples subjected different ageing conditions and containing three different fibre contents. The laboratory experimental programs are indirect tensile test at 25°C and repeated load axial test at 40°C. The results showed that the fibres improved the mixture’s performance. The main findings obtained at 25°C for short and long-term ageing reveal that low fibre content at around 0.3% per aggregate weight display a stiffness modulus up to 14% higher than that of unmodified mixtures, hence showing that fibres may improve the bearing capacity and rut-resistance of asphalt mixtures. Conversely, as the amount of fibre increases to 0.5% and 0.7%, the stiffness decreases to the point of becoming unacceptably low, almost 80% lower than unmodified mixes stiffness. However the data also reveal that high fibre contents at 0.5% and above completely neutralize the impact of ageing on the mixture, indicating that fibre-modified mixtures would yield longer lives