Numerical modeling of shape and topology optimisation of a piezoelectric cantilever beam in an energy-harvesting sensor

Piezoelectric materials are excellent transducers for converting mechanical energy from the environment for use as electrical energy. The conversion of mechanical energy to electrical energy is a key component in the development of self-powered devices, especially enabling technology for wireless sensor networks. This paper proposes an alternative method for predicting the power output of a bimorph cantilever beam using a finite-element method for both static and dynamic frequency analyses. A novel approach is presented for optimising the cantilever beam, by which the power density is maximised and the structural volume is minimised simultaneously. A two-stage optimisation is performed, i.e., a shape optimisation and then a “topology” hole opening optimisation

Separation of oil from oil water emulsion by the use of alginate gel encapsulated iron oxide and graphene oxide nanoparticles

Thesis (M.S.) University of Alaska Fairbanks, 2017Crude oil is used extensively around the world as a source of energy and as a means of producing various petroleum products. However, apart from being an excellent energy source, crude oil can also be a major pollutant in the form of oil spills. Crude oil spills can occur on land and in the ocean during the drilling, production, transportation or storage stages. While it is possible to reduce the damage caused to the environment by an oil spill, it is almost impossible to completely remove the adverse effects. New techniques need to be developed to clean-up oil spills at higher rates and with increased efficiency. The use of nanoparticles (NPs) for oil spill clean-up has gained popularity in recent years. This research focuses on the use of alginate gel as an immobilizing agent for nanoparticles that are then used for the removal of heating oil from an oil-water mixture. Iron Oxide and Graphene Oxide Nanoparticles were immobilized using sodium alginate in calcium chloride. The concentration of the nanoparticles was varied from 1 g/L to 5 g/L. The immobilized nanoparticles were then added to an oil-water mixture which was prepared by spiking heating oil in methanol and adding the solution to deionized water to achieve uniform distribution. 10 mL samples containing residual oil were extracted from the heating oil and water mixture at regular intervals and were analyzed for the residual oil. Measurements were carried out for residual hydrocarbons using Gas Chromatography/Mass Spectroscopy (GC/MS), Fluorescence Spectroscopy and Ultraviolet--visible spectroscopy (UV-Vis). Results from GC/MS show the highest percentage of oil being removed from the mixture by 2 g/L iron oxide (77%) and 2 g/L graphene oxide (81%) NPs. Analysis for residual hydrocarbons based on the time of contact showed promising results, with 75% of oil removed in 70 minutes. Further, based on the data obtained it was observed that the nanoparticles reached saturation after 70 minutes and were unable to remove additional quantities of oil from the mixture. Changing the nanoparticles from Iron Oxide to Graphene Oxide increased the amount of oil removed by 4%. This research will assist future development of oil spill clean-up and water treatment techniques that make use of nanoparticles as sorbents

Coinage in Roman Syria: 64 BC - AD 253

The thesis examines the production, circulation and significance of coinage in northern Syria during the first three centuries of Roman control of the province. The coinages of the region are distinct and share features which justify their study as a group. The thesis includes a catalogue of the issues produced by the thirteen cities in the region which minted coins, and the coinage of the Kingdom of Commagene. A study of site finds, drawn from published excavations and first-hand examination of unpublished material in the middle east, hoards, and countermarks, highlights features of the patterns of circulation of these coinages in Syria, as well as 'foreign' issues circulating in the region. The distribution of Syrian issues outside Syria, the longevity of coins in circulation, and the effects of debasements of the silver coinage upon the circulating medium are also considered. Central to the study is the coinage of Antioch, one of the major imperial mints in the Roman Empire whose coinage has been largely neglected, and has never been fully catalogued until now. Separate sections study the metrology and denominational structure of sequences of issues, and broader surveys cover the relationship of Syrian coinage to that of other provinces and to that of Rome itself. The thesis considers ways in which the Syrian coinage can be used to understand better aspects of other provincial and Roman imperial coinages, such as to what extent the Roman provinces had a consistent 'monetary' policy in the eastern provinces, and whether the coinage of Rome was viewed as a 'preferred currency' in the east, as some scholars have suggested. The survey ends in AD 253, when it is suggested that imperial policy regarding Syrian coinage might have changed, and when coinage of a Greek type ceases in the region

Using isotonic magnesium sulfate nebulization as an adjuvant treatment for moderate acute exacerbation of bronchial asthma (aeba) in adult comparing with salbutamol alone: a double blinded, randomised control trial

Objective The aim of this study is to evaluate the efficacy of single dose nebulized magnesium sulfate in augmenting bronchodilatory effect of salbutamol in acute asthma as compare to salbutamol alone. In addition, we also observe for any significant reduction in total treatment duration in this two study groups. Methodology This was a double blinded, randomized controlled trial, conducted in Emergency Department of Hospital Universiti Sains Malaysia, Kelantan between 1st October 2013 and 1st October 2014. We enrolled a total of 120 patients with moderate acute exacerbation of bronchial asthma, all the patients were then randomized into two groups via block randomization technique. Group A (n=60) nebulized with salbutamol only (5mg), Group B (n=60) nebulized with isotonic magnesium sulfate (7.5% w/v) plus salbutamol (5mg). Blood pressure, pulse rate, respiratory rate, oxygen saturation and peak expiratory flow rate (PEFR) of each patient were measured at baseline and at 20 minutes post-treatment. Total duration of treatment started from time of enrollment until achievement of predicted PEFR > 80% was recorded. Results The 60 patients enrolled in each treatment arm had comparable baseline demographic and clinical characteristics. At 20 minutes post-treatment, Group A and Group B showed statistically significant improvement in PEFR (100±61 L/min and 87±42 L/min respectively, p value <0.001). Group B showed significant reduction of mean respiratory rate and improvement in mean oxygen saturation (p value <0.001). However, there were no statistically significant differences in means improvement of PEFR and reduction of total duration of treatment between two groups. We did not observe any adverse effect from treatment at all time. Conclusion In conclusion, the use of MgSO4 as an adjuvant to salbutamol nebulization in moderate AEBA patient does not show any superiority in their therapeutic effect in comparing to salbutamol alone. However, paired t-test done on group B population has shown the feasible bronchodilatory property of MgSO4, it is able to bring about a statistically significant decrease in respiratory rate and improvement in oxygen saturation. In future study, we suggest a pilot study to be conducted to establish the dose-response relationship of magnesium sulphate in the treatment of acute asthma before a larger, multicentre trial is proposed

The EM Algorithm

The Expectation-Maximization (EM) algorithm is a broadly applicable approach to the iterative computation of maximum likelihood (ML) estimates, useful in a variety of incomplete-data problems. Maximum likelihood estimation and likelihood-based inference are of central importance in statistical theory and data analysis. Maximum likelihood estimation is a general-purpose method with attractive properties. It is the most-often used estimation technique in the frequentist framework; it is also relevant in the Bayesian framework (Chapter III.11). Often Bayesian solutions are justified with the help of likelihoods and maximum likelihood estimates (MLE), and Bayesian solutions are similar to penalized likelihood estimates. Maximum likelihood estimation is an ubiquitous technique and is used extensively in every area where statistical techniques are used. --

An effective optimisation method for multifactor and reliability-related structural design problems

This thesis first presents a systematic design procedure which satisfies the required strength and stiffness, and structural mass for conceptual engineering structural designs. The procedure employs a multi-objective and multi-disciplinary (MO–MD) optimisation method (multifactor optimisation of structure techniques, MOST) which is coupled with finite element analysis (FEA) as an analysis tool for seeking the optimum design. The effectiveness of the MOST technique is demonstrated in two case studies.Next, a reliability-related multi-factor optimisation method is proposed and developed, representing a combination of MOST (as a method of multi-factor optimisation) and the reliability-loading case index (RLI) (as a method of calculating the reliability index). The RLI is developed based on a well-known reliability method: the first-order reliability method (FORM). The effectiveness and robustness of the proposed methodology are demonstrated in two case studies in which the method is used to simultaneously consider multi-objective, multi-disciplinary, and multi-loading-case problems. The optimised designs meet the targeted performance criteria under various loading conditions.The results show that the attributes of the proposed optimisation methods can be used to address engineering design problems which require simultaneous consideration of multi-disciplinary problems. An important contribution of this study is the development of a conceptual MO–MD design optimisation method, in which multi-factor structural and reliability design problems can be simultaneously considered

Randomized control study using vitamin d ( calcitriol) in preventing post total thyroidectomy transient hypocalcemia

Objective: The aim of our open label randomized control study was to determine the incidence of transient hypocalcemia developing post total thyroidectomy in Kelantan (Malaysia) and the benefit of pre-operative treatment using oral vitamin D for post total thyroidectomy. Methodology: This is a randomized control study which recruits a total of 74 patients from Hospital Universiti Sains Malaysia and Hospital Raja Perempuan Zainab II. The study was carried out over one year duration since 5th May 2009 until 30th April 2010. The ethical approval was obtained from The Research Ethical Committee (Human), Universiti Sains Malaysia and Ethical Board Clinical Research Center (CRC), Ministry of Health. Seventy four patients that underwent total thyroidectomy were randomized into two groups. Study group: 37 patients treated with oral vitamin D (calcitriol) 1.5ug/day for 2 days duration before operation followed by 1.0ug/day plus oral calcium lactate 1800mg/day for 7 days after operation. Control group: 37 patients did not receive oral Vitamin D or calcium lactate. All the patient were assessed clinically and biochemically forhypocalcemia. Result: There was no significant difference between the study and control group in terms of demographic distribution of age, sex, diagnosis, surgeon, operating duration, parathyroid gland autotransplant, and baseline level of serum calcium, phosphate and intact PTH. The incidence of post total thyroidectomy transient hypocalcemia in the study group is about 16.7% compared with control group of 75%. Among the cases, 50.0% in the study group and 64.3% in control group are symptomatic. The incidence of permanent hypoparathyroidism is 2.7%. There was significant difference in term of incidence of asymptomatic hypocalcemia and symptomatic hypocalcemia between these two groups since p value is <0.001. There was also significant difference between control and study group with regards to the trend of post-operative serum calcium changes since p value <0.001. However, there was no significant difference in the risk of developing permanent hypoparathyroidism. The post operative stay is significantly longer in control group, 4.59 days compared with study group, 3.92 days ( p value : 0.001). Conclusion: The administration of oral vitamin D pre-operatively had significantly reduced the incidence of transient hypocalcemia post total thyroidectomy

Modelling and optimisation of a bimorph piezoelectric cantilever beam in an energy harvesting application

Piezoelectric materials are excellent transducers in converting vibrational energy into electrical energy, and vibration-based piezoelectric generators are seen as an enabling technology for wireless sensor networks, especially in selfpowered devices. This paper proposes an alternative method for predicting the power output of a bimorph cantilever beam using a finite element method for both static and dynamic frequency analyses. Experiments are performed to validate the model and the simulation results. In addition, a novel approach is presented for optimising the structure of the bimorph cantilever beam, by which the power output is maximised and the structural volume is minimised simultaneously. Finally, the results of the optimised design are presented and compared with other designs

Sensitivity Analysis of Wave Forces on Monopod Platform under Metocean Condition by Simulation

Stokes wave theory for deep water condition is employed in PETRONAS Technical Specification (PTS) for all water condition in Peninsular Malaysia Operation, Sarawak Operation and Sabah Operation. This research aims to address this through predicting wave forces from wave theories using simulation study and analyzing the sensitivity of wave forces to wave theories and deviated wave height criteria. In PTS, for 100-year storm event, the wave height criteria recorded shows fluctuation of 140% from the wave height criteria for operating event. With reference to this, it is feasible to adopt a deviation of ±40% with assumption that the wave height is reduced to 40% less is during the extreme low tidal waves. Wave theories are used in theoretical predictions of wave kinematic using the measured wave height, wave period and water depth. Extensive literature review has been done to better understand the wave forces, water condition and prediction wave kinematics by wave theories. Structural Analysis Computer Software (SACS) v3.5 is used as the main tools in the methodology. The monopod structure is modeled in SACS for PMO, SKO and SBO region. Stokes wave theory is identified as conservative for monopod structure design in PMO zone. For SKO zone, the wave force is recognized as sensitive towards wave theories. Based on analysis result, Cnoidal wave theory is identified as conservative over other applicable wave theories. Samarang in SBO zone is having transitional water condition. Wave force is recognized to be changing sensitively by Cnoidal wave theory. Analysis results reflected that Cnoidal is more conservative due to more critical values of wave forces predicted, higher order wave theory and best describe the transitional water condition