Optimise repair strategy selection and repair knowledge sharing to support aero engine design.

Recent growth in aviation industry, large civil jet engines OEMs (Original Equipment Manufacturer) and MROs ((Maintenance, Repair and overhaul)) have emphasised on decreased profits, poor technology selections and maintenance focused design. This has generated service based approach in their selling, offering all customers’ requirements, known as servitisation. The servitisation has increased profits but did not solve the challenges of poor technology selection and design. The difficulties involved within servitisation entails rationalised decision making often with high risk and very limited information. This thesis assesses the most suitable Multi-criteria decision making (MCDM) in concurrence with OEMs and MRO focus groups that recognises the industrial requirements and proposed a novel selection method which is an AHP algorithm based on MCDM in efforts to address business KPIs in aero engine servitisation. This AHP algorithm based MCDM develops an optimised repair process/technology selection framework which is called ORSS (Optimised Repair Selection Strategy). The ORSS applies the business KPIs (Quality Cost Delivery) as a selection criteria combined with the repair engineer's requirements and expert's evaluation of processes/technologies based on a component and its damage-mode to provide the optimised repair process/technology selection that also compliments the components lifecycle repair strategy. A structured knowledge sharing framework has also been developed. This consists of the information that the designers can update to help repair teams to become more effective and efficient in repair and services critical information tasks. These frameworks were validated successfully by experts within the design, repair and service teams at Rolls Royce. These frameworks have shown high levels of improvements in repair process selection and the key knowledge sharing for designs.Engineering and Physical Sciences (EPSRC)PhD in Manufacturin

Management of intercondylar femur fracture with distal femur locking compression plate: outcome analysis of 72 cases

Background: Supra-condylar and inter-condylar fractures of the distal femur account for 7% of all femoral fractures and have always been difficult to treat and regaining full knee function is often difficult. The purpose of this study is to evaluate the functional outcome, fracture healing, complications of distal femoral intercondylar fractures managed by locking compression plate.Methods: Total 72 patients of intercondylar femur fracture were operated by ORIF with distal femur-locking compression plate via the standard swashbuckler approach. The functional outcomes were analyzed using modified hospital for special surgery scoring system.Results: Muller type C2 fracture was the most common fracture type with 50 out of 72 patients. The average range of motion achieved was about 99.03°±24.73° (Closed fractures =105.83°±19.41°and open fractures = 89.50°±28.36°). There was also a significant difference in the duration of operative time, 84.28±18.32 minutes for closed fractures and 98.46±22.47 minutes for open fractures. The average duration for radiological union was 14.52±2.21 weeks for closed and 17.20±2.44 weeks for open fractures. The average knee score was 80.13±13.38 using modified Hospital for Special Surgery score.Conclusions: Closed fractures have a higher range of motion and a better knee score compared to open fractures, supporting the fact that soft tissue compromise also affects range of motion and post-op rehabilitation of the limb. The outcome seems to correlate with the nature of injury i.e. high vs low velocity, type of fracture, anatomic reduction, associated injuries, time elapsed since injury to fixation and the stability of fixation

Effects of induction machine parameters on its performance as a standalone self excited induction generator

A squirrel cage induction machine (SCIM) when aggregated with relevant capacitances and a prime mover, acts as self-excited induction generator (SEIG). As it hosts energy conversion the parameters of SCIM have considerable impact on the power extraction capability of SEIG. An aspect which is missing from the available research on SEIGs is evaluation of the affects of its rotor's moment of inertia (J) and per-phase stator winding resistance (Rs) on performance indices. This work investigates the impacts of these factors on a SCIM's performance as series compensated, short shunt SEIG. The study considers two distinctly designed SCIMs, in terms of J and Rs, operated as SEIG. In order to simulate their performance a stationary reference frame dq model including non-linear saturation and cross coupling effects is developed and verified experimentally. Several key investigations based on series capacitance selection, losses and efficiency, on-load performance with different power factor loads, transient performance with load perturbation and variable speed operation are carried out. The study reveals that SEIG with high J and lower Rs gives considerably better performance than its counterpart. The conclusions reported in the study are important especially for standalone/off grid application of SEIGs.This publication was made possible by Qatar University Collaborative Research grant # [ QUCG-CENG-21/22-1 ] from the Qatar University . The statements made herein are solely the responsibility of the authors. The APC for the article is funded by the Qatar National Library, Doha, Qatar.Scopu

Diagnosis of Faulty Elements in Array Antenna using Nature Inspired Cuckoo Search Algorithm

Detection and correction of faulty elements in a linear array have great importance in radar, sonar, mobile communications and satellite. Due to single element failure, the whole radiation pattern damage in terms of side lobes level and nulls. Once we have detect the position of defective element, then correction method is applied to achieve the desired pattern. In this work, we introduce a nature inspired meta-heuristic cuckoo search algorithm to diagnose the position of defective elements in a linear array. The nature inspired cuckoo search algorithm is new to the optimization family and is used first time for fault detection in an array antenna. Cuckoo search algorithm is a global search optimization technique. The cost function is used as a fitness function which defines an error between the degraded far field power pattern and the estimated one. The proposed technique is used effectively for the diagnosis of complete, as well as, for partial faulty elements position. Different simulation results are evaluated for 40 elements Taylor pattern to validate and check the performance of the proposed technique

Mental health services for youth in the Eastern Mediterranean Region: Challenges and opportunities (Editorial)

The Global Burden of Disease study shows that the burden from mental and substance use disorders, measured in Disability Adjusted Life Years (DALYs), has steadily risen in the Eastern Mediterranean Region (EMR) over the last three decades and is higher than the global average for almost all EMR countries). Even more alarming is the finding that depression, self-harm, anxiety and conduct disorders constitute four of the top 10 causes of DALYs among girls and boys aged 15-19 years and suicide is a leading cause of adolescent mortality

Effects of Emblica Officinalis Extract Cream on Human Skin Trans-epidermal Water Loss Measured with Non Invasive Probe

The purpose of this study was to assess hydroalcoholic Emblica officinalis fruit extract cream on human skin trans-epidermal water loss (TEWL). Ten male volunteers were examined in this study. Measurements were made on cheeks. Creams with different concentrations of ABIL® EM 90 and liquid paraffin containing 3% hydroalcoholic Emblica officinalis fruit extract were developed and tested for stability studies for a period of 28 days. Selected cream and its base were further assessed in different conditions at 8 °C (in refrigerator), 25 °C (in incubator), 40 °C (in incubator) and 40 °C (in incubator) with 75% relative humidity (RH) for color, odor, thickness, grittiness liquefaction, phase separation, and pH at different time intervals. Trans-epidermal water loss (TEWL) was monitored every week by non-invasive bio-instrument Tewameter MPA 5. All measurements were made statistically by ANOVA and t-paired test. Significant decrease on skin TEWL was produced. Keywords: Hydroalcoholic Emblica officinalis fruit extract, Facial cream, Biophysical paramete

Clinical profile and outcome of infective endocarditis at the Aga Khan University Hospital

Background: The spectrum of infective endocarditis (IE) is significantly different in developed and developing countries. The present study was conducted to study the clinical profile and outcome of infective endocarditis in Pakistan.Methods: A descriptive cross-sectional study with review of medical records for 188 patients admitted to our teaching hospital with a diagnosis of IE from January 1988 to December 2001. One hundred fifty-nine subjects fulfilled the modified Duke diagnostic criteria.Results: Definite IE was found in 59.7% (95/159) patients, while the rest had possible IE. One-third of subjects had acute IE 55/159 (34.5%). Subacute IE was found in 62% (99/159) and Nosocomial IE in 3% of the cases. Eighty six (54%) were classified as having culturenegative endocarditis and 73 (46%) as culture positive. Ninty four patients (59%) had an underlying predisposing factor including congenital heart disease (31%) and rheumatic heart disease (21%). The most frequently isolated organisms were streptococci (52%) and followed by staphylococci (29%). Fourteen (8.1%) patients had right-sided cardiac involvement. Using univariate analysis, patients with heart failure, neurologic or renal complications, septicemia, nosocomial endocarditis, and prosthetic valve endocarditis were at increased risk of death (p ≤ 0.05), however no individual microorganism, or specific site, size, or morphology of vegetation seen on echocardiogram were significantly associated with death. Thirty-seven (23%) patients died of endocarditis or its complications.Conclusion: Endocarditis continues to be an important contributor to morbidity and mortality in Pakistan, especially in young adults. Our patients differ from the west in terms of epidemiology, predisposing factors, microbiology, complications, and outcom

A novel hybrid methodology to secure GOOSE messages against cyberattacks in smart grids

: IEC 61850 is emerging as a popular communication standard for smart grids. Standardized communication in smart grids has an unwanted consequence of higher vulnerability to cyber-attacks. Attackers exploit the standardized semantics of the communication protocols to launch different types of attacks such as false data injection (FDI) attacks. Hence, there is a need to develop a cybersecurity testbed and novel mitigation strategies to study the impact of attacks and mitigate them. This paper presents a testbed and methodology to simulate FDI attacks on IEC 61850 standard compliant Generic Object-Oriented Substation Events (GOOSE) protocol using real time digital simulator (RTDS) together with open-source tools such as Snort and Wireshark. Furthermore, a novel hybrid cybersecurity solution by the name of sequence content resolver is proposed to counter such attacks on the GOOSE protocol in smart grids. Utilizing the developed testbed FDI attacks in the form of replay and masquerade attacks on are launched and the impact of attacks on electrical side is studied. Finally, the proposed hybrid cybersecurity solution is implemented with the developed testbed and its effectiveness is demonstrated