This paper presents an efficient thermal energy harvesting IC (EHIC) that supports a battery-less ?Watt system-on-chips. The EHIC consists of an inductor-based DC-DC converter that boosts a low input voltage to a suitable output level. Further, a switched capacitor buck converter is utilized to regulate the boost converter output voltage and support multiple output voltage levels, namely 0.6V, 0.8V and 1V. In low energy mode and to enhance the efficiency, the EHIC is capable of bypassing the switched capacitor so that the load is driven directly from the boost converter. The prototype chip is fabricated in 65nm CMOS and occupies an area of less than 0.46mm2 Measured results confirm an efficiency of 65% at 0.6V output voltage and 42?W. In addition, the end-toend peak efficiency is 71% at 0.8V output voltage and 182?W.
This work presents a novel application of a high gain adaptive observer-based technique for Lithium-ion (Li-ion) battery modelling. The model used in our paper was originally developed by Chen and Mora. However, in Chen and Mora's original work, the parameters required for the battery model were estimated through intensive experimentation. In contrast, this work presents an adaptive observer for estimating the battery model parameters, which results in a reduction of experimental effort required when the battery parameters are estimated.
Power generation from renewable energy resources is on the increase in most countries, and this trend is expected to continue in the foreseeable future. In an effort to enhance the integration of renewable power generation from solar and wind into the traditional power network, there is need to address the vulnerabilities posed to the grid as a result of the intermittent nature of these resources. Variability and ramp events in power output are the key challenges to the system operators due to their impact on system balancing, reserves management, scheduling and commitment of generating units. This paper presents a novel technique based on forecasting to guarantee optimal dispatch of hybrid Wind and Photovoltaic Power Systems (with minimal use of Battery Energy Storage) based on a case study of the 50 MW Wind Power Project under development in the Sultanate of Oman.
Proportional Integral controllers tuned using classical methods may exhibit poor performance under external disturbances or sudden load changes. Fractional Order Proportional Integral (FO-PI) controllers are expected to perform better in terms of load disturbance rejection due to their Iso-damping property. This paper investigates the potential of an FO-PI controller for the speed control of an indirect field oriented (IFO) induction motor drive system with cascaded current control. The motor is first approximated with a first order plus dead time (FPDT) model and consequently an optimal FO-PI controller is designed. The FO-PI controller is implemented in both simulation and experimentation and shows better performance than its integer order counterparts.
Post-combustion technology of carbon capture and storage (CCS) is highly suitable to reduce the CO2 released from combustion processes into the atmosphere. Alkanolamines have been widely studied for this purpose and found to have high rate of reaction with CO2 as well as high CO2 loading and low heat of absorption which are the required properties for an efficient CO2 capture. Results of the experimental work being reported shows 2MAE as a suitable amine for carbon capture as it has a CO2 loading of 1.35 mole CO2/mole amine. Blends of 2MAE with three selected tertiary amines (2DMAE, TMDAP and MDEA) were tested at 40oC for a total concentration of 30% weight amines. For the total of 30% weight of aqueous amines, the 2MAE is varied as 0%, 5%, 10%, 15% and 30% while the respective tertiary amine makes the remaining part to make a total of 30%.
Tea, Camellia sinensis, is an agricultural product and one of the most popular and international drinks, so it attracted an increasing attention to quality and safety. Pesticide residues are major chemical contaminants found in tea samples. During farming the pesticide may be used to minimize problems of pests. An accurate, rapid and reliable method for the simultaneous determination of many pesticide residues in the imported tea to the UAE by liquid and gas chromatography coupled with tandem mass spectrometry [LC-MS/MS] and GC-MS/MS will be used. Samples will be purified by a modified quick, easy, cheap, effective, rugged, safe (QuEChERS) method, followed by analysis by LC-ESI (+)-MS/MS and quantification using internal standards. In this research, in-house validation method will be applied to the quantification of the pesticide residues contained in real tea samples obtained from local markets, which greatly improve the detection performance and the range of the pesticide multi-residues.
In this work we are developing sensitive and selective method for detection and quantitation of cathinone related compounds using GC-MS after indirect chiral derivatization with trifluoroacetyl-l-prolyl chloride (TPC) to achieve enantiomeric separation of some of the cathine and cathinone derivatives. More than 30 compounds of synthetic cathinones are separated to their optical enantiomers successfully by using a 60m HP5-MS capillary column. Nikethamide was used as internal standard in cathinones quantitation which has similar chemical structure to cathinones. 12 of cathinones derivatives were separated in one chromatogram after spiking in urine sample. Calibration curves of selected 12 cathinones derivatives in urine were constructed for 5, 10, 20, 50, 100, 200 ppm.
Different solvents have been tested for dissolving HKUST-1 Metallic Organic Framework and PEBAX-4533 for the preparation of Mixed Matrix Membranes by Solvent Evaporation Method. An equivalent ratio of NMP and Ethanol solvents achieved homogeneous solutions of both HKUST-1 and PEBAX-4533 individually. Although a good dispersion was achieved after adding HKUST-1 into the polymer solution, the resultant films could not be removed from the casting dish. Dimethyl Sulfoxide was then tested for PEBAX-MOF mixture but after stirring overnight at 110?C it contained many chunks and again could not be removed from the casting dish. greasing the casting dish before casting the solutions helped in removing the films but they were either ductile or inhomogeneous. Dimethyl Formaldehyde was the solvent of choice which gave films with very good filler dispersion. The optimum membrane preparation method such as mixing temperature and duration was established after carrying out several experiments.
There has been an increasing interest in task-based language teaching (TBLT) as an educational framework by second language acquisition (SLA) researchers. TBLT is a teaching methodology in which classroom tasks constitute the main construct of instruction. It is based on ideas issuing from the philosophy of education, SLA theories, and empirical findings on effective instructional techniques. While research regarding this area is growing worldwide, there is a very little experimental research in the Gulf area and United Arab Emirates (UAE) in particular. Accordingly, my study investigates the qualitative differences in teachers' enactment of TBLT in intermediate English as a foreign language (EFL) classrooms in UAE, concentrating primarily on the way teachers focus on form (FonF) in a TBLT-based context. The study also aims to explore teachers' and students' attitudes towards the implementation of this framework and figure out the properties, complexities, and limitations that evolve from such application.
Bilingual literacy model had been constantly implemented in the kindergartens of Abu Dhabi Education Council (ADEC) with co-teachers educating children integrated language and subject areas in ways that assist acquiring English and Arabic languages. This study investigated the quality of the bi-literacy co-teaching program in terms of its alignment with the National Association for the Education of Young Children (NAEYC)'s standards from the perspectives of Arabic and English teachers and administrative staff in one of Al Ain city's kindergartens. Following a qualitative design, focus groups and interviews were the tools used to collect data about the phenomena of the program practices, and then data was analyzed into themes that reflected the evaluation standards. The discussion resulted in a thorough understanding of teachers' views and practices at different elements of the educational process as well as the general strengths and weaknesses of the bi-literacy co-teaching program in kindergarten.
