Retinal vessel segmentation is a critical biomedical image processing task, it requires high accuracy. There are two types of vessels, thick vessels and thin vessels. The challenge lays in the segmentation of the thin vessel branches. Another challenge in the class imbalance between vessel pixels and non-vessel pixels. As the non-vessel pixels outnumber the thin lines of pixels of the vessels [1]. To reduce the effect of the class imbalance, a proposed segmentation model will be the U-net architecture trained to multiple datasets. The datasets are DRIVE, STARE, HRF, and CHASE-DB. The datasets were initially resized to DRIVE dataset dimensions. Then, the model was trained with all datasets. Lastly it was tested on all datasets together and individually. The F1-score has increases by 0.84%, 1.94%, and 0.27%, for STARE, HRF and CHASE-DB. The sensitivity of the model showed improvement in 2.46%, 7.1%, and 3% for STARE, HRF and CHASE-DB.
Genome imputation is an approach that builds on the statistical grounds of hidden Markov models to facilitate Genome-wide association studies (GWAS) at a lower cost. It uses the haplotype patterns in a reference panel to estimate the missing SNPs in a study target. In this study, we show that the use of a local UAE panel provides higher imputation results imputing UAE samples than existing international reference panels. The usage of the UAE reference panel resulted in concordance value of 98.6% as opposed to 97.1% for the 1000 genome and 96.4% for the combined panel in the case of chromosome 17, and has shown a higher number of correctly imputed variants using the UAE reference panel across all chromosomes for minor allele frequency below 0.5. Achieved results using IMPUTE2, 120 WGS, 1000 genotype array data sets provided by Khalifa University.
This work experimentally investigates the mechanical behavior of a novel modified auxetic honeycomb structure. In auxetic honeycomb structures, the internal members of the cell shaped as 'V' yields undesired interactions causing distortion and instability of the structure under compression. This issue is addressed by flattening the internal members through the addition of an extra member. The new design results in a significant improvement in mechanical properties through the introduction of a secondary linear elastic region. In this work, we experimentally investigate the elastic behavior of the new design in attempt to expand the investigation to include analytical modeling and FEM validation. In addition, we introduce a Fusion Deposition Modeling (FDM) 3D printing process that yields isotropic structures.
Bucky papers with thickness of more 400 ?m are very important for many applications such as Radar Absorbing Materials (RAM), Electromagnetic interference shielding (EMI), supercapacitors and lithium-ion battery (LIB). CNT Buckypaper is a thin sheet made from an aggregate of carbon nanotubes, literature studies show the thickness of single bucky paper produced by film casting method is in the range of 40-100 ?m1. This study shares the preliminary work carried as an attempt to produce super-thick bucky papers by film casting process.
In this work, the development of laminate structural battery components is attempted. Two methods; spray coating and doctor blade assisted slurry casting, are attempted in view of coating the anodic current collector with active materials. Additionally, the compounding of solid polymer electrolyte in a co-rotating twin-screw extruder is investigated computationally. A steady-state computational model is set up in Ansys-Fluent environment to understand the effect of compounding solid phase in the melt. Preliminary results indicate spray coating method to provide better dispersion over the surface area of the electrodes. The pressure contours in the kneading zone 1 show maximum pressures of 35MPa at the periphery of kneading disks, reducing to approximately 2MPa at kneading zone 4. Process optimization is underway to obtain the best possible parameter combination to obtain a uniform coating of the electrodes and a uniform distribution of conductive fillers in the extrudate.
In this paper, the piezoresistive response of reduced graphene oxide (rGO) coated glass fabric is utilized to monitor thermally induced shape memory recovery response of a polyurethane shape memory polymer (SMP) 4-layer glass fiber fabric composite. Static thermal cycling and shape memory recovery experiments are performed and compared in order to differentiate and separate the thermal and strain induced piezoresistive response of the coated fabric. Initial results show clear and identifiable impact of shape memory recovery on the piezoresistive response where critical milestones of recovery process such as the beginning and the end of recovery along with the speed of recovery can be obtained from piezoresistive data which shows the viability of utilizing rGO coated fabrics and by extension carbon nanomaterials coated fabrics as means to monitor the shape memory response of SMP composites.
CubeSats are standardized miniatured satellites invented in 1999 and are extensively used in space exploration due to its low mission cost for applications such as remote sensing or communication. However, it is essential to stabilize the CubeSat to achieve its mission requirements. CubeSats can be controlled actively using significant power consuming actuators or by no-powered passive techniques. The aim of this research is to successfully develop, simulate and verify an effective approach to passively control the satellite attitude by modelling environmental disturbances; hence, reducing the reliance on control actuators. As a result, improving the survivability and maximizing the benefits that can be obtained from a mission.
Accurate thermal analysis of CubeSat in the design process is extremely necessary due to the absence of an active thermal control system. In this work, the effects of various thermal sources affecting Cubesats in orbit are considered. A detailed thermal model of MYSat-1 was developed using Ansys Workbench software. The average heat incidents on each surface of MYSat-1 for a whole day are calculated using CubeSat Wizard software. A simulation was conducted for a whole year, from this simulation a random day was selected to perform the simulation in Ansys. Steady-state condition thermal analysis was considered to reduce the computation time. The results of Ansys simulations were compared with the housekeeping data of MYSat-1 and CubeSat Wizard. The findings of this study showed that the thermal model is fairly acceptable.
This paper is concerned with the thermal housekeeping data generated onboard a 1U CubeSat in low earth orbit. The actual flight data was collected using 14 temperature sensors and then used to validate a numerical multi-physics model for CubeSats. The model is based on a single isothermal node approach and takes into account the orbital parameters as well as the eclipse and the solar illumination cycles on each surface of the CubeSat. In addition, the model includes the effects of the albedo and Earth Infrared heat fluxes. The presented simulations and results from the validated model were used to draw conclusions on the worst hot and cold case scenarios for MYSAT-1. In addition, a sensitivity analysis was carried out to investigate the assumed specific heat capacity effect on the generated temperature cycles
Fruits, and nuts encapsulate their embryos with a tough outer shell to protect them from predation and other environmental risks. In this paper, we look at the behavior of the Corymbia calophylla Nut, also known as Marri, under compression in comparison to other well-studied nuts such as Macadamia, Walnut, and Pistachio. This is done by 1) Exploring the role different nut orientations has on the fracture strength of the Marri 2) Creating 3D models of the nut using CT scan images and a combination of modeling software to remove the effect of its heterogeneous nature 3) performing compression tests on the 3D printed structures of the nut and comparing results with the original nuts. This structure-function study has the potential to motivate the design of new stronger bioinspired materials for various applications
