Jessore, Bangladesh
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Roy S.,JUST | Kabir I.,JUST | Al-Mamun K.M.A.,JUST
2016 International Conference on Innovations in Science, Engineering and Technology, ICISET 2016 | Year: 2016

Here, the optoelectronic performance of lattice matched InGaAs/InP vertical cavity surface emitting LASER is numerically simulated using MATLAB in (100), (110), (111), (113) and (131) crystal orientation by solving an eight-band k.p Hamiltonian using finite difference scheme including spin-orbit coupling. Tensor plane rotation formulae is applied to change the wave-vector k and Hamiltonian from orthodox (100) plane orientation. It is shown that there is a notable interrelationship between optical emission spectra and crystal plane orientations. The highest and lowest gains are estimated in (111) and (100) orientations with their respective peak emission wavelengths of 1770nm and 1680 nm at the carrier injection density of 2.5 × 1018 cm-3. The outcome of this paper would be a stimulus to design ultra-speed optoelectronic devices with performance amelioration by using non-100 oriented epitaxial layers. © 2016 IEEE.

News Article | June 6, 2017

Tubelip wrasses eat dangerously, daring to dine on sharp corals lined with stinging cells. New images reveal the fish’s secret to safe eating: lubing up and planting a big one on their dinner. “It is like sucking dew off a stinging nettle. A thick layer of grease may help,” says David Bellwood, a marine biologist at James Cook University in Townsville, Australia, who snapped the shots with his colleague Victor Huertas. Of roughly 6,000 fish species that roam reefs, just 128 consume corals. These corallivores specialize in different menus. Well-studied butterfly fish, for example, use their long, thin snouts to nip up coral polyps, the tiny animals that build corals. Tubelip wrasses such as Labropsis australis of the South Pacific are known for nibbling coral with their luscious lips, but until now, it was unclear what part of the coral the fish were eating or how they were eating it. While the surface of the wrasse’s lips looks smooth to the naked eye, convoluted grooves appear under a scanning electron microscope, the team reports June 5 in Current Biology. Mucus-producing cells line each groove. In contrast, the lips of a wrasse species that doesn’t eat corals (Coris gaimard) are sleek and sport fewer slime-secreting cells. Video footage of L. australis shows that the fish feeds by latching onto coral with its lips and sucking. The slime probably protects the fish’s lips from stinging cells that line the coral skeleton and also serves as a sealant, allowing the wrasse to get suction against the coral’s razorlike ridges. “Their kiss is so hard it tears the coral’s flesh off its skeleton,” Bellwood says. The team suspects that the fish feed primarily on mucus layers and sometimes tissue that lines the sharp skeleton. So, essentially the fish are using their lip mucus to better harvest the coral’s mucus. Mucus is, in general, a hot commodity in the marine ecosystem. Some fish use it as sunscreen, others for speed — it can reduce drag through the water. Cleaner wrasses even eat slime off the skin of other fish (SN: 8/2/03, p. 78). Given the threats that coral reefs face from bleaching events and climate change, having fish that suck their flesh might seem a tad brutal. But whether the added stress of snot-eating fish serves as a mere nuisance or a serious threat remains to be studied.

2nd International Conference on Electrical Information and Communication Technologies, EICT 2015 | Year: 2015

A numerical approach is presented to calculate crystal orientation-dependent effective mass of heavy hole, light hole and spin-orbit split-off hole of III-V semiconductors (GaAs, InAs, InP, GaSb, and InSb etc.) at Gamma-point by envelope approximation using k.p method. Unitary transformation is used to modify the wave vector and eight-band k.p Hamiltonian is applied in conventional (100) crystal orientation. The simulation is carried out for conventional crystal orientations (100), (110) and (111) as well as non-conventional orientations (113), (131) and (201). It is found that there is a substantial correlation between the effective mass and the crystal orientation. The results obtained from conventional crystal orientations are compared with that of estimated by well-established PBE, HSE and MBJLDA methods and found to have within good agreement. This indicates that the proposed technique can be applied to evaluate effective mass in arbitrary orientation of III-V semiconductors. It is also found that (113) orientation possesses lowest effective mass than other orientations. The outcome of this paper would be a boost to design high-speed optoelectronic devices with improved performance by introducing non-100 oriented epitaxial layers. © 2015 IEEE.

Poddar S.,Banglalink Digital Communication Ltd. | Roy S.,JUST | Hasan M.T.,AIUB
ICEEE 2015 - 1st International Conference on Electrical and Electronic Engineering | Year: 2015

A dual triangular cut resonator (DTCR) design of a patch antenna is proposed. The antenna is able to perform at 2.44 GHz band applicable for wireless local area networks. The gain and directivity are 7.75 dB and 8.29 dBi, respectively. Proposed cut resonator develops stored capacitive charge and boosts the antenna radiation and electromagnetic field which enhances the antenna performance. © 2015 IEEE.

Diaz O.,University of New Mexico | Xu F.,University of New Mexico | Min-Allah N.,COMSATS Institute of Information Technology | Khodeir M.,JUST | And 3 more authors.
IEEE Communications Letters | Year: 2012

Network service recovery from multiple correlated failures is a major concern given the increased level of infrastructure vulnerability to natural disasters, massive power failures, and malicious attacks. To properly address this problem, a novel path protection solution is proposed to jointly incorporate traffic engineering and risk minimization objectives. The framework assumes probabilistic link failures and is evaluated against some existing multi-failure recovery schemes using network simulation. © 2012 IEEE.

Al-Rousan N.,Taibah University | Al-Rousan M.,JUST | Shareiah A.,JUST
2012 International Conference on Renewable Energy Research and Applications, ICRERA 2012 | Year: 2012

Renewable energy is the energy that comes from natural resources and it is the energy that naturally replenished and can be converted from a form to another to be useful for human usage. Solar energy is one form of renewable energy that can be obtained from sun through the form of solar radiation. It is a promising alternative technology that will help to replace petroleum energy sources. However, there are many problems to use such as technology which limits the produced energy. The major problem is the poor efficiency of solar cells and the high cost. Tracking systems are used to maximize electricity output of solar cells. However, this is not a naive task due to the difficulty in finding a general rule that can be used to get optimal output of solar cells for all situations. Moreover, different environments may affect the output of solar cells. Artificial Intelligence could be used to control these parameters for better efficiency. So; the aim of this paper is to introduce an efficient tracking model for the solar panel set that maximizes the energy output of the solar system in the area of Jordan and its neighbors based on practical experiment. The proposed fuzzy model was experimentally evaluated to demonstrate that this system can successfully predict the correct angles with superior results when it provides any average low error rate of 3.55% for predicted tilt angles and 4.1% degrees for predicted orientation angles. This low predicted error indicates that the system can be used efficiently in Jordan and its neighbors to predict the directions to collect the maximum power. © 2012 IEEE.

Haddad B.,University of Jordan | Jarrah A.,JUST
Journal of Circuits, Systems and Computers | Year: 2013

Recent demand for low power VLSI circuits has been pushing the development of innovative approaches to reduce power dissipation. Supply voltage (V CC) and switching activity factor (α) are main sources of dynamic power dissipation in CMOS technology. Furthermore, the power dissipation increases exponentially by the value of supply voltage. New approach based on switching activity analysis and multiple supply voltage is implemented successfully in logical circuits, taking in mind the critical path(s) of the design and switching activity factor of each element in the design. High supply voltage is applied on elements on the critical path(s). Elements off the critical path(s) are classified into categories according to their switching activity factors. The total power dissipation is reduced, while the propagation delay remains without any increase. The proposed approach combines the concepts of critical/non-critical paths and switching activity analysis to assign different VCCs to different elements. © 2013 World Scientific Publishing Company.

Hamdan M.A.,University of Jordan | Al-Nimr M.A.,J.U.S.T. | Hammoudeh V.A.,University of Jordan
Journal of Fluids Engineering, Transactions of the ASME | Year: 2010

In this work, the effect of the second-order term to the velocityslip/temperature-jump boundary conditions on the solution of four cases in which the driving force is fluctuating harmonically was studied. The study aims to establish criteria that secure the use of the first order velocity-slip/temperature-jump model boundary conditions instead of the second-order ones. The four cases studied were the transient Couette flow, the pulsating Poiseuille flow, Stoke's second problem, and the transient natural convection flow. It was found that at any given Kn number, increasing the driving force frequency, increases the difference between the first and second-order models. Assuming that a difference between the two models of over 5% is significant enough to justify the use of the more complex second-order model, the critical frequencies for the four different cases were found. For the cases for which the flow is induced by the fluctuating wall as in cases 1 and 3, we found that critical frequency at Kn=0.1 to be ω=8. For the cases of flow driven by a fluctuating pressure gradient as in case 2, this frequency was found to be ω = 1, at the same Kn number. In case 4, for the temperature-jump model, the critical frequency was found to beω = 7 and for the velocity-slip model the critical frequency at the same Kn number was found to be ω = 1.35. Copyright © 2010 by ASME.

Alkhateeb A.,Jordan University of Science and Technology | Karasneh J.,JUST | Abbadi H.,Jordan University of Science and Technology | Hassan A.,University of Baghdad | Thornhill M.,University of Sheffield
Journal of Oral Pathology and Medicine | Year: 2013

Background: Recurrent aphthous stomatitis (RAS) is a common oral ulcerative condition. At ulcer sites vascular adhesion molecule-1 (VCAM-1), E-selectin and intercellular adhesion molecule-1 (ICAM-1) are strongly expressed on blood vessels, and ICAM-1 is expressed on keratinocytes. Expression of these molecules would promote leukocyte accumulation and invasion of the epithelium. Thus, polymorphisms in these candidate genes might contribute to RAS susceptibility. We investigated whether the inheritance of specific selectin, ICAM and VCAM gene polymorphisms is associated with RAS susceptibility. Methods: Ninety-six RAS cases and 153 controls were recruited from a Jordanian population. Blood was collected for hematological investigations and genotyping. Six SNPs were genotyped: E-selectin rs5361 and rs1805193, L-selectin, rs2205849, ICAM-1 rs5498, ICAM-5 rs885743 and VCAM-1 rs1800821. Association was determined using chi-square and binary logistic regression analysis after correcting for confounding factors. Linkage disequilibrium was determined using the EH program, and the Phase 2.1 program was used to construct and compare haplotypes between cases and controls. Results: There was a significant association of the A allele (Pcorr = 0.027), AA and AC genotypes (OR = 10.9 and 9.0, respectively) of the E-selectin rs5361 gene polymorphism and TAA haplotype (rs2205849, rs5361, and rs1805193, respectively; P = 0.03) with RAS. None of the other SNPs showed a significant association. Conclusions: This is the first report to link inheritance of the A allele, AA and AC genotypes of the E-selectin rs5361 polymorphism with increased risk of RAS. Further studies in different patient cohorts are needed to confirm the association, and functional analyses might clarify the biological significance of the association. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Just | Date: 2015-11-06

Computer software to enable uploading, downloading, accessing, posting, displaying, and otherwise providing electronic media and information related to the fashion industry via computer and communication networks; computer software for accessing, browsing and searching online databases related to the fashion industry.

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