Faculty of Engineering(FOE)

NiFe films were pulse electrodeposited on conductive copper substrates under galvanostatic mode with and without the presence of an ultrasonic field at different pulse current magnitudes and duty cycles. The optimum deposition condition was found to be at a current magnitude of 40 mA and a duty cycle of 50.00% under ultrasonic treatment. This deposition condition has significantly reduced the surface roughness from 39.01 1.1 nm to 6.96  1.1 nm and the spherical grain size in the range from 579.40 nm -623.30 nm to 29.00 nm -46.90 nm. On the other hand, the resistivity was reduced to 19.86 µcm from 54.00 µcm as the Ni content increased from 76.08% to 80.12 % for achieving good stoichiometry for NiFe thin films. Through the optimization study, the deposition current is observed to be the dominant factor in determining the single phase deposition of NiFe film whereas ultrasonic field and duty cycle significantly reduces the surface roughness and the spherical grain size, all of which combine to reduce film resistivity.

A summary is provided of presentations and discussions from the NASA Radiation Biomarker Workshop held September 27-28, 2007, at NASA Ames Research Center in Mountain View, California. Invited speakers were distinguished scientists representing key sectors of the radiation research community. Speakers addressed recent developments in the biomarker and biotechnology fields that may provide new opportunities for health-related assessment of radiation-exposed individuals, including for long-duration space travel. Topics discussed include the space radiation environment, biomarkers of radiation sensitivity and individual susceptibility, molecular signatures of low-dose responses, multivariate analysis of gene expression, biomarkers in biodefense, biomarkers in radiation oncology, biomarkers and triage following large-scale radiological incidents, integrated and multiple biomarker approaches, advances in whole-genome tiling arrays, advances in mass-spectrometry proteomics, radiation biodosimetry for estimation of cancer risk in a rat skin model, and confounding factors. Summary conclusions are provided at the end of the report.

In this study, thorough review is performed on various reported fabrication techniques of the Perovskite Solar Cell (PSC) and the Hole Transport Materials (HTM) layer, in order to provide a critical insight on the direction for further advancement in related fields as well as a better understanding on the device physics. So far, the best short-circuit current density of 22.9 mA/cm 2 has been reported in CH 3 NH 3 PbI 3-x Cl x scaffold by TiCl 4 nanorods treated by NRS and the best open circuit voltage of 0.763V has been reported in TiO 2 /perovskite/spiro-OMeTAD/Au. On the other hand, so far the highest PCE of the PSCs reported in the literature is 19.3%. Interestingly, PSC with 200nm mesoporous TiO 2 has been reported to achieve PCE value of 16.46%. A 5-layer TiO 2 /perovskite/spiro-OMeTAD/Au integrated with 40 nm ZnO thin film has been reported to achieve Fill Factor (FF) of 76%. Although promising data has been obtained through numerous researches, there are still many other optimizations yet to be done before mass commercialization of PSC is possible. Optimizing the fabrication process of carrier transport material as well as the incorporation of sensitizer into the device structure are the key aspects that should be focused on in future researches.

Due to several climate changes caused by greenhouse gas and to the increasing need for clean energies, scientists drew attention to renewable energy sources, which are the most suitable solution in the future. Sparsely populated and flat open terrains observed in Batna region (North East of Algeria) and its semi-arid climate, make it a promising region for the development of solar and wind energies. In this article, we analyzed ten years of daily wind speed data in a remote area of Batna: Mustafa Ben Boulaid Airport. Wind power availability, as well as annual mean values of wind speed and power, were estimated. Frequency distribution of daily totals of wind speed data were counted and illustrated too. The results have been used to estimate net energy output of different wind turbines. This simulation shows a difference in wind generators production and allows us to choose the best wind turbine adapted to site conditions. Since solar and wind energy resources may be used to compensate each other, we evaluated also the solar potential of the same area.

Although the mixed-host organic light emitting diode (OLED) has been known for improved performance, the charge injection and mobility may not be uniform in the light emitting layer (EML) hence affecting the exciton formation and recombination. In this work, we investigate the effects of concentration profiles of electron-and hole-transport materials in EML on the charge injection and confinement as a result of in-situ formation of transport layers by thermal evaporation of a pre-mixed source. Experimental results show that the OLED performance depends on the continuously graded concentration profiles, and are correlated to numerical simulations which reveal charge confinement, spatial shift of recombination zone and lowering of hole mobility.

Wind energy varies with year, season, and time of day, elevation above ground, and form of terrain. Because of fluctuating nature of the wind speed the variation of the output power occurs. When wind speed exceeds the rated speed of a turbine, the output power also exceeds the rated level. By controlling the pitch angle the output power of the wind turbine can be limited. The purpose of this work is to design a MATLAB\SIMULINK model of a wind turbine using pitch controller where at high wind speed region, the pitch controller will automatically active to maintain the output power at the rated level. From simulation result, it is observed that, at rated wind speed pitch angle is zero i.e. pitch controller remains inactive and above rated wind speed the pitch controller is activated and keep the output power at rated value by changing the value of pitch angle.

The fabrication of organic photovoltaics (OPVs) from non-hazardous nanoparticulate (NP) inks offers considerable promise for the development of ecofriendly large-scale printed solar modules. However, the typical NP core−shell morphology (driven by the different donor/acceptor affinities for the surfactant used in NP synthesis) currently hinders the photovoltaic performance. As such, surfactant engineering offers an elegant approach to synthesizing a more optimal intermixed NP morphology and hence an improved photovoltaic performance. In this work, the morphology of conventional sodium dodecyl sulfate (SDS) and 2-(3-thienyl) ethyloxybutylsulfonate (TEBS)-stabilized poly(3-hexylthiophene) (P3HT) donor:phenyl-C 61-butyric acid methyl ester (PC 61 BM) acceptor NPs is probed using scanning transmission X-ray microscopy, UV−vis spectroscopy, grazing-incidence X-ray diffraction, and scanning electron microscopy. While the SDS-stabilized NPs exhibit a size-independent core−shell morphology, this work reveals that TEBS-stabilized NPs deliver an intermixed morphology, the extent of which depends on the particle size. Consequently, by optimizing the TEBS-stabilized NP size and distribution, NP-OPV devices with a power conversion efficiency that is ∼50% higher on average than that of the corresponding SDS-based NP-OPV devices are produced.

The fabrication of organic photovoltaics (OPVs) from non-hazardous nanoparticulate (NP) inks offers considerable promise for the development of ecofriendly large-scale printed solar modules. However, the typical NP core−shell morphology (driven by the different donor/acceptor affinities for the surfactant used in NP synthesis) currently hinders the photovoltaic performance. As such, surfactant engineering offers an elegant approach to synthesizing a more optimal intermixed NP morphology and hence an improved photovoltaic performance. In this work, the morphology of conventional sodium dodecyl sulfate (SDS) and 2-(3-thienyl) ethyloxybutylsulfonate (TEBS)-stabilized poly(3-hexylthiophene) (P3HT) donor:phenyl-C 61-butyric acid methyl ester (PC 61 BM) acceptor NPs is probed using scanning transmission X-ray microscopy, UV−vis spectroscopy, grazing-incidence X-ray diffraction, and scanning electron microscopy. While the SDS-stabilized NPs exhibit a size-independent core−shell morphology, this work reveals that TEBS-stabilized NPs deliver an intermixed morphology, the extent of which depends on the particle size. Consequently, by optimizing the TEBS-stabilized NP size and distribution, NP-OPV devices with a power conversion efficiency that is ∼50% higher on average than that of the corresponding SDS-based NP-OPV devices are produced.

Although the mixed-host organic light emitting diode (OLED) has been known for improved performance, the charge injection and mobility may not be uniform in the light emitting layer (EML) hence affecting the exciton formation and recombination. In this work, we investigate the effects of concentration profiles of electron-and hole-transport materials in EML on the charge injection and confinement as a result of in-situ formation of transport layers by thermal evaporation of a pre-mixed source. Experimental results show that the OLED performance depends on the continuously graded concentration profiles, and are correlated to numerical simulations which reveal charge confinement, spatial shift of recombination zone and lowering of hole mobility.

and development of atherosclerosis. Adhesion molecules are upregulated by ox-LDL and numerous inflammatory cytokines and play a pivotal role in atherogenesis. In this study, we examined whether diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS), 3 major organosulfur compounds of garlic oil, reduce adhesion molecule expression induced by ox-LDL and, if so, through what mechanism. Human umbilical vein endothelial cells were preincubated with 1 mmol/L DAS, 200 mmol/L DADS, or 100 mmol/L DATS for 16 h and then with 40 mg/L ox-LDL for an additional 24 h. ox-LDL induction of cellular and cell surface expression of E-selectin and vascular cell adhesion molecule (VCAM)-1 was suppressed by garlic allyl sulfides in the order DATS . DADS . DAS. The adhesion of HL-60 cells to endothelial cells was inhibited 27 and 33% and the production of cellular peroxides was inhibited 43 and 50% by DADS and DATS, respectively (P , 0.05). ox-LDL alone dephosphorylated protein kinase B (PKB) and cAMP responsive element binding protein (CREB); such deactivation was reversed by DADS and DATS. Electrophoretic mobility shift assay showed that the activation of CREB binding to DNA was consistent with changes in CREB phosphorylation. The protein kinase A (PKA) inhibitor H89 reversed the suppression of VCAM-1 by DADS and DATS, but the phosphoinositide 3-kinase (PI3K) inhibitor wortmannin had no effect. In contrast, wortmannin abolished DADS-and DATS-induced suppression of ox-LDL-induced E-selectin expression. These results suggest that the suppression of ox-LDL-induced E-selectin and VCAM-1 expression by DADS and DATS and, thus, monocyte adhesion to endothelial cells is likely dependent on the PI3K/PKB or PKA/CREB signaling pathway in an adhesion molecule-specific manner. To our knowledge, this is the first report that garlic modulates ox-LDL-mediated leukocyte adhesion to human endothelial cells through the PKB and PKA pathways. J. Nutr. 138: 996-1003, 2008. 7 Abbreviations used: CREB, cAMP responsive element binding protein; DADS, diallyl disulfide; DAS, diallyl sulfide; DATS, diallyl trisulfide; DCF-DA, 2#,7#dichlorodihydrofluorescein diacetate; EMSA, electrophoretic mobility shift assay; HUVEC, human umbilical vein endothelial cells; ICAM, intercellular adhesion molecule; IL, interleukin; OSC, organosulfur compounds; ox-LDL, oxidized LDL; PI3K, phosphoinositide 3-kinase; PKA, protein kinase A; PKB, protein kinase B; ROS, reactive oxygen species; TNF, tumor necrosis factor; VCAM, vascular cell adhesion molecule.

Hospitals and medical centers produce a tremendous amount of sequential images for medical examinations such as MRI, CT and Fluoroscopy. This series of images takes up a large amount of storage space, in addition to the cost and time incurred during transmission. For medical data, lossless compression is preferable to the greater gains of lossy compression, in the interest of reliability. This paper proposes a new method for lossless compression of pharynx and esophagus fluoroscopy images, depending on correlation and combination of Run Length and Huffman. Otherwise, the shifted images moved to a shifted group and compress separately. From the experimental results obtained, the proposed method achieved improved performance with a compression ratio of 12.2 for the proposed combination of Run-length and Huffman coding (R. Huff) on the difference images as compared to 1.35 for the standard method.

Medical institutions generate an enormous amount of medical images for examinations such as fluoroscopy, where each examination of a patient consists of a collection of images. This takes up a large amount of valuable storage space, in addition to the amount of time and cost incurred during transmission. Although lossy compression provides for better compression, lossless compression is usually required and expected for medical diagnosis. This paper proposes a new method for a lossless compression on oesophagus fluoroscopy images using correlation. The differences of pairs or sequence of images are classified based on correlation. From the experimental results obtained, the proposed method achieved improved performance with a compression ratio of 7.97 as compared to standard Huffman coding (HM) loss less compression. Recent years have seen a tremendous increase in the generating, transmission and storage of medical images. Many researchers have been working towards developing approaches for compressing medical images. Compression techniques can be classified into two main categories: lossless and lossy. Typically, lossless image compression is necessary for medical applications, where perfect accuracy is expected in maintaining the same quality of the original image for medical diagnosis. Nevertheless it comes at the expense of obtaining low compression ratios (Onsy 2007).

Diagnostic imaging devices such as fluoroscopy produce a vast number of sequential
images, ranging from localization images to functional tracking of the contrast agent
moving through anatomical structures such as the pharynx and esophagus. In this paper,
an effective method for lossless and diagnostically lossless compression of fluoroscopic
images is proposed. The two main contributions are: (1) compression through blockbased
subtraction matrix division and adaptive Run Length Encoding (RLE), and (2)
range conversion to improve the compression performance. The region of coding (RC)
– in this case the pharynx and esophagus, is effectively cropped and compressed using
customized correlation and the combination of Run-Length Encoding (RLE) and
Huffman Coding (HC), to increase compression efficiency. The experimental results
show that the proposed method is able to improve the achieved compression ratio by
488% as compared to that of the benchmark traditional methods.

Systematic procedures for data storage and retrieval are obligatory to the fluoroscopy
and other conventional diagnostic imaging devices in which they produce a large
number of medical images. This paper proposes and efficient method for lossless
compression of fluoroscopic images. There are two components in this paper;
segmentation and compression. For the rectangular inside the image, a scheme on
automated segmentation and extraction was developed. The development includes the
derivation of the general equation with the purpose of extracting the rectangle, then
perform lossless compression of targeted parts within fluoroscopy images. In this paper,
the cropped region of interest (ROI) are pharynx and esophagus whereby it goes
through the extraction and compression process. To improve the compression
efficiency, the correlation and combination of Run Length and Huffman coding are
used in the extraction and compression stage. The experimental results of the proposed
method have shown that the achieved compression ratio show has improved by 400%
when compared to traditional techniques.

Image de-noising is a core operation in image
processing and computer vision. In this paper, combination of
two popular methods in image de-noising bilateral and
anisotropic-diffusion filtering is investigated to reduce the noise
in medical images, while preserving the clarity of images. The
proposed method experimented on 23 MRI images. The results
obtained from the proposed method gained higher peak signal to
noise ratio (PSNR) and compression ratio (CR) performance in
comparison with the traditional methods by more than 8%.