Conference Papers

D2SH2: Robotics & Automation

Identification and PID tuning of quadrotor pitch channel using MRFT

Mohamad Chehadeh (The Petroleum Institute, UAE); Igor Boiko (Petrolum Institute, UAE)

Abstract

In this paper, we present a novel method for quadrotor modeling and tuning of PID gains using the Modified Relay Feedback Test (MRFT). We show how to obtain the transfer function for the pitch channel of the quadrotor and how to design the PID such that they minimize the ITSE performance index. The proposed method provides several advantages over classical modeling approach.

D2SI2: Micro/Nano Systems

Microfluidic DEP separation device for detection of cancer cells in blood

Nicholas Hallfors, Anas Alazzam and Bobby Mathew (Khalifa University, UAE)

Abstract

Here we describe the development of a novel microfluidic device for separation of cancer cells from diluted blood by Dielectrophoresis (DEP). The separation is based on the balance between dielectrophoretic and hydrodynamic forces. A microfluidic platform is fabricated using standard microfabrication techniques. The device consists of a glass substrate and a PDMS block. The present technique could be applied to find incident cancer at any stage and size that is not yet detectable by standard diagnostic techniques. The AC signals used in the separation are 20 V peak-to-peak with frequencies of 10-100 kHz.

GaAs0.7P0.3/Si Dual Junction Tandem "Step-Cell" Under Solar Concentration

Sabina Abdul Hadi (Masdar Institute of Science and Technology, UAE); Eugene A. Fitzgerald (Massachusetts Institute of Technology, USA); Ammar Nayfeh (Masdar Institute of Science & Technology, UAE)

Abstract

In this work we present performance of a GaAs0.7P0.3/Si tandem step-cell under concentration. Step-cell is a multi-junction solar cell with bottom cell partially exposed to direct sunlight in order to boost current in the bottom cell. Results show that optimum solar concentration is 50 suns with efficiency increasing from ~31.5% under 1 sun to ~34.5% under 50 suns. This work shows that relatively low concentration provides maximum efficiency boost for III-V/Si dual junction step-cell and that optimum step-cell design does not change significantly with solar concentration.

Aluminum Doped ZnO as Anti-reflective Coating for Solar Cell Applications

Muhaira Al Eghfeli (Masdar Institute, UAE)

Abstract

Simulation and fabrication of Aluminum doped Zinc Oxide (AZO)) as Antireflective coating (ARC) for thin film-Si solar cell has been studied. Results showed that optimum performance is for absorber doping NA = 1016 cm-3 and ZnO ARC thickness of 70 nm. 14.78?ficiency and 83? is reported for the modeled device in this work (with ZnO ARC). 90-nm thick ZnO layer is found to have the lowest reflectance that reaches less than 5% in the wavelength range from 2000 to 3000 nm. In addition, we fabricate a-Si solar cells with AZO ARC using Atomic Layer Deposition.

Structural and electrical properties of (MOS) structures prepared by electrophoreses deposition of gold nano-particles on Aluminum/ Hafnium oxides

Ghada Dushaaq (UAE, Abu Dhabi & Masdar Institute of Science & Technology, UAE); Mahmoud Rasras (Masdar Institute of Technology, UAE); Ammar Nayfeh (Masdar Institute of Science & Technology, UAE)

Abstract

Aluminum/ Hafnium oxides on p-type Si substrate with embedded gold (Au) nanoparticles (GNP) were prepared using Atomic layer deposition (ALD) and electrophoreses deposition (EPD) methods. Ultra high resolution scanning electron microscopy (HRSEM) has been used to study the GNP distribution on Al2O3/HfO2 thin films as a function of samples dipping time. Layers of GNP at the Al2O3/HfO2 /Si interface were formed with approximately (6-9) nm thickness, thick films of GNP can be achieved for longer time of deposition. Capacitive-Voltage measurements have been carried out on the metal-oxide-semiconductor structures under high frequency (1MHz) and the results show wider hysteresis loop for MOS capacitor with higher time of deposition.

Evaluation of Piezoresistive Sensors for Shoe-Integrated Weight Measurements

Nisrein Sada (Masdar Institute of Science and Techonolgy, UAE)

Abstract

Congestive heart failure(CHF) affects 10% of the world's population above 65 years . One of the main symptom of CHF is edema and recent studies have shown that it can be detected from weight increase up to two weeks before hospitalization. In this work, we explore the use of shoe-mounted pressure sensors to continuously, automatically and remotely estimate the weight. We have conducted an experimental study of various pressure sensors. Our study has revealed that the pressure sensors used in wearable applications exhibit undesirable properties for precise weight measurements. Specifically, we have measured and characterized creep, repeatability and noise problems that limit the accuracy and reliability of weight estimates. Our experimental study includes force sensitive resistors, flexiforce, Velostat, Neoprene, and semiconductive polymer composite materials. Different materials have been evaluated for sensor electrodes and packaging such as copper plates, neoprene and conductive fabrics in order to reduce noise and creep.

D2SJ2: Civil Engineering

Sustainable High-Performance Self-Compacting Concrete with Recycled Ceramic Waste Powder

Sama Aly (United Arab Emirates University, UAE); Amr El-Dieb (United Arab Emirates University & College of Engineering, UAE); Mahmoud Taha (University of New Mexico, USA)

Abstract

Various regulating actions were imposed by governments and environmental organizations all over the world to seize the negative impact on the ecosystem resulting from huge amounts of solid waste materials being dumped in landfills causing major environmental problems. Recycling of industrial by-products is a step forward towards sustainable waste management. Utilization of ceramic waste powder (CWP) in the construction and building industry as a partial replacement for cement will play a significant role in energy conservation and generation of CO2. This study will focus on determining the optimum percentage of CWP to yield high-performance selfcompacting concrete (HPSCC) with acceptable fresh and hardened characteristics. The inclusion of CWP as an alternative constituent material will be evaluated through various tests (i.e. slump flow, J-ring, column segregation test, strength, and durability).

Identification of factors affecting cost overruns in UAE's road projects

Ihsan AlHosani and Senthilkumar Venkatachalam (University of Sharjah, UAE)

Abstract

Cost performance is a concern particularly for critical infrastructure projects such as road projects. The UAE's road projects too suffer from cost overruns. Hence, there is a need for a study substantiation to identify the causes and its possible solutions. Literature on cost overruns was reviewed to understand global perception and its major causing causes. With this background, the study focuses on identifying the main reasons of cost overruns in UAE road projects. The data were collected through structured questionnaire survey from various project participants and it was analyzed in term of frequency, severity and importance indices. Investigation on causes of cost overruns with respect to the identified 44 common factors was done. Based on analysis, the top five reasons causing cost overruns are delays in decisions making by approval authorities, changes in client requirements, construction cost underestimation, poor site management and frequency of variation orders and additional works.

Regional Frequency Analysis based on New River Network Information in Arid and Semi-arid Regions

Kichul Jung, Taha Ouarda and Prashanth Marpu (Masdar Institute of Science and Technology, UAE)

Abstract

Regional frequency analysis procedures are generally used to provide information to design hydraulic structures such as irrigations, recharge dams, and reservoirs at ungauged locations. In this analysis, the proper use of river network characteristics plays an important role in obtaining hydrological variable estimation. The objective of the present work is to present new physiographical and meteorological variables associated with the drainage network features by improving the accuracy of flood quantile estimation in arid and semi-arid regions, USA. The 105 stations including streamflow records are used for the analysis. The model to estimate flood quantiles consists of artificial neural networks and canonical correlation analysis. The tenfold cross-validation approach is applied to assess the model performance. Based on the study, it is observed that the new physiographical and meteorological variables affect the performance of the proposed models by enhancing the accuracy of flood quantile estimation.

A closed form solution for pull-out strength of variable modulus post-installed anchors

Mohd Khan and Kumar Shanmugam (MIST, UAE)

Abstract

Stress transfer through the interlayer of the adhesively bonded post installed anchors with spatially varying adhesive stiffness is predicted using a shear-lag model and hence will be used in determining the pull-out strength of these anchors in comparison with homogeneous bondline anchors. A closed-form solution is presented for the arbitrary distribution of shear stiffness of the bondline considering both bonded and debonded embedded-end conditions. For validation, the distribution of shear stress along the bondline is compared with that of equivalent axisymmetric Finite Element (FE) models and the results are found to be in good agreement. The theoretical solution developed can be readily used to evaluate the pull-out performance of post-installed adhesive anchors. Variable stiffness adhesive interfaces deserve an interest in practical applications to estimate the effect of loss of interface stiffness due to degradation of the adhesive material.

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