Thermal and Nonthermal Lattice Gas Models for a Dimer-trimer Surface Catalytic Reaction: A Monte-Carlo Simulation Study

K. Iqbal,Parvaiz A. Khand 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.3

We have studied the kinetics of an irreversible dimer-trimer reaction of the type 2 A_3 + 3 B_2 ! 6 AB by considering the precursor motion of the dimer (B_2) on a square, as well as on a hexagonal surface, by using a Monte Carlo simulation. When the movement of precursors is limited to the first nearest neighborhood, the model gives reactive window widths of the order of 0.22 and 0.29 for the square and the hexagonal lattices, respectively, which are quite large compared to those predicted by the Langmuir-Hinshelwood (LH) model. The phase diagrams resemble qualitatively to those of standard Ziff, Gulari and Barshad (ZGB) model. The width of the reactive window of the precursor model depends upon the mobility of the precursors. The continuous transition disappears when the motion of precursors is extended to the third nearest neighborhood. The diffusion of B atoms to adjacent vacant sites, as well as desorption of the dimer (B_2) from the surface with a certain probability (P), is also considered.

Inequalities for the derivative of polynomials with restricted zeros

N. A. Rather,Ishfaq Dar,A. Iqbal 강원경기수학회 2020 한국수학논문집 Vol.28 No.4

For a polynomial $\mathit{P(z)=\sum_{\nu =0}^{n}a_{\nu}z^{\nu}}$ of degree $\mathit{n}$ having all its zeros in $\mathit{|z|\leq k,k \geq 1}$, it was shown by Rather and Dar \cite{1} that $$\max_{|z|=1} |P^{\prime}(z)|\geq \frac{1}{1+k^n}\bigg(n+\frac{k^n|a_n|-|a_0|}{k^n|a_n|+|a_0|}\bigg)\max_{|z|=1}|P(z)|.$$ In this paper, we shall obtain some sharp estimates, which not only refine the above inequality but also generalize some well known Tur\'{a}n-type inequalities.

Quality Assessment of Beef Using Computer Vision Technology

Md,Faizur Rahman,Abdullah Iqbal,Md,Abul Hashem,Akinbode A,Adedeji 한국축산식품학회 2020 한국축산식품학회지 Vol.40 No.6

Imaging technique or computer vision (CV) technology has received huge attention as a rapid and non-destructive technique throughout the world for measuring quality attributes of agricultural products including meat and meat products. This study was conducted to test the ability of CV technology to predict the quality attributes of beef. Images were captured from longissimus dorsi muscle in beef at 24 h post-mortem. Traits evaluated were color value (L*, a*, b*), pH, drip loss, cooking loss, dry matter, moisture, crude protein, fat, ash, thiobarbituric acid reactive substance (TBARS), peroxide value (POV), free fatty acid (FFA), total coliform count (TCC), total viable count (TVC) and total yeast-mould count (TYMC). Images were analyzed using the Matlab software (R2015a). Different reference values were determined by physicochemical, proximate, biochemical and microbiological test. All determination were done in triplicate and the mean value was reported. Data analysis was carried out using the programme Statgraphics Centurion XVI. Calibration and validation model were fitted using the software Unscrambler X version 9.7. A higher correlation found in a* (r=0.65) and moisture (r=0.56) with ‘a*’ value obtained from image analysis and the highest calibration and prediction accuracy was found in lightness (r²c=0.73, r²p=0.69) in beef. Results of this work show that CV technology may be a useful tool for predicting meat quality traits in the laboratory and meat processing industries.

Diversity of pollinators and their role in the pollination biology of chickpea, Cicer arietinum L. (Fabaceae)

Abdul Latif,Saeed Ahmad Malik,Shafqat Saeed,Naeem Iqbal,Qamar Saeed,Khalid Ali Khan,Chen Ting,Hamed A. Ghramh 한국응용곤충학회 2019 Journal of Asia-Pacific Entomology Vol.22 No.2

Chickpea (Cicer arietinum L.) is an important source of food for people worldwide. In the current study, we studied its pollination biology with special reference to floral visitors along with their visitation rate, frequency and pollen load during 2012 and 2013. We also explored the effect of floral visitors on the capsule weight, seed weight, seed numbers and seed germination. Results revealed three bees, two wasps, five flies, one moth and three butterfly species on the flowers of chickpea. Apis dorsata, A. florea, Amegilla sp. and Eristalinus aeneus were the major species with 434–474, 223–311, 69–74 and 81–136 individuals, respectively in both years. Floral visitors differed significantly in term of visitation frequency with A. florea as the most frequent visitor (9.13–9.86 visits/flower/5 min) followed by E. aeneus (5.43–5.58 visits/flower/5 min) and A. dorsata (1.72–2.31 visits/ flower/5 min) in both years. Similarly, A. florea had statistically highest visitation rate (16.85–19.99 flowers visited/min) followed by E. aeneus (9.73–10.68 flowers visited/min). A. dorsata had significantly higher pollen load on its body (84629–85,104 pollen grains) followed by A. florea (64940–65,135 pollen grains) and Amegilla sp. (64020–65,120 pollen grains). The open-pollinated flowers had significantly higher capsule weight (0.27 ± 0.01 g), seed weight (0.18 ± 0.01 g), seed numbers (1.67 ± 0.07 seeds) and seed germination (95 ± 1.38%) as compared to flowers deprived of pollinators in cages. The results suggested A. florea, A. dorsata and E. aeneus could be effective pollinators of chickpea. Hence these three species can be properly utilized on commercial scale to increase crop yield.

The fourth element: characteristics, modelling and electromagnetic theory of the memristor

Kavehei, O.,Iqbal, A.,Kim, Y. S.,Eshraghian, K.,Al-Sarawi, S. F.,Abbott, D. The Royal Society 2010 Proceedings, Mathematical, physical, and engineeri Vol.466 No.2120

<P> In 2008, researchers at the Hewlett-Packard (HP) laboratories published a paper in <I>Nature</I> reporting the development of a new basic circuit element that completes the missing link between charge and flux linkage, which was postulated by Chua in 1971 (Chua 1971 <I>IEEE Trans. Circuit Theory</I>18 , 507-519 ( doi:10.1109/TCT.1971.1083337 )). The HP memristor is based on a nanometre scale TiO 2 thin film, containing a- doped region and an undoped region. Further to proposed applications of memristors in artificial biological systems and non-volatile RAM, they also enable reconfigurable nanoelectronics. Moreover, memristors provide new paradigms in application-specific integrated circuits and field programmable gate arrays. A significant reduction in area with an unprecedented memory capacity and device density are the potential advantages of memristors for integrated circuits. This work reviews the memristor and provides mathematical and SPICE models for memristors. Insight into the memristor device is given via recalling the quasi-static expansion of Maxwell’s equations. We also review Chua’s arguments based on electromagnetic theory. </P>

Lack of Association of a Common Polymorphism in the 3'-UTR of Interleukin 8 with Non Small Cell Lung Cancer in Kashmir

Bhat, Imtiyaz Ahmad,Pandith, Arshid A.,Bhat, Bashir A.,Naykoo, Niyaz A.,Qasim, Iqbal,Rasool, Roohi,Aziz, Sheik Aejaz,Shah, Zafar Amin Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.7

Background: Chronic inflammation is considered as an important factor in the pathogenesis of lung cancer. The presence of inflammatory cells and higher levels of pro-inflammatory cytokines in the tumor microenvironment and their surrounding tissues is gaining much importance in research. Materials and Methods: One hundred ninety NSCLC cases and 200 age, smoking and sex matched controls were evaluated for association of IL-8 -251 (rs4073) and IL-8 -845 (rs2227532) in our population. Restriction fragment length polymorphism (RFLP) was used followed by direct sequencing for the detection of SNPs. Results: The IL-8 -845 polymorphism was not found in our population. No significant association was observed between the IL-8 -251 AT genotypes and IL-8 -25 AA genotypes and NSCLC (p=0.05) in our population. The IL-8 -251 A allele was also non-significant (p=0.05) in NSCLC patients. Conclusions: In conclusion, this report reveals lack of association between IL-8 - 251 A/T polymorphism and NSCLC in our Kashmir Valley population.

Configuration assessment of MR dampers for structural control using performance-based passive control strategies

Wani, Zubair R.,Tantray, Manzoor A.,Iqbal, Javed,Farsangi, Ehsan Noroozinejad Techno-Press 2021 Structural monitoring and maintenance Vol.8 No.4

The use of structural control devices to minimize structural response to seismic/dynamic excitations has attracted increased attention in recent years. The use of magnetorheological (MR) dampers as a control device have captured the attention of researchers in this field due to its flexibility, adaptability, easy control, and low power requirement compared to other control devices. However, little attention has been paid to the effect of configuration and number of dampers installed in a structure on responses reduction. This study assesses the control of a five-story structure using one and two MR dampers at different stories to determine the optimal damper positions and configurations based on performance indices. This paper also addresses the fail-safe current value to be applied to the MR damper at each floor in the event of feedback or control failure. The model is mathematically simulated in SIMULINK/MATLAB environment. Linear control strategies for current at 0 A, 0.5 A, 1 A, 1.5 A, 2 A, and 2.5 A are implemented for MR dampers, and the response of the structure to these control strategies for different configurations of dampers is compared with the uncontrolled structure. Based on the performance indices, it was concluded that the dampers should be positioned starting from the ground floor, then the 2^nd floor followed by 1^st and rest of the floors sequentially. The failsafe value of current for MR dampers located in lower floors (G+1) should be kept at a higher value compared to dampers at top floors for effective passive control of multi-story structures.

Generation of sub-ppb level vapor phase mixtures of biogenic volatile organic compounds from liquid phase standards and stepwise characterization of their volatilization properties by thermal desorption-gas chromatography-mass spectrometry

Iqbal, M.A.,Kim, K.H. Elsevier 2014 Journal of chromatography Vol.1373 No.-

In the analysis of biogenic volatile organic compounds (BVOCs) in ambient air, preparation of a sub-ppb level standard is an important factor. This task is very challenging as most BVOCs (e.g., monoterpenes) are highly volatile and reactive in nature. As a means to produce sub-ppb gaseous standards for BVOCs, we investigated the dynamic headspace (HS) extraction technique through which their vapors are generated from a liquid standard (mixture of 10 BVOCs: (1) α-pinene, (2) β-pinene, (3) 3-carene, (4) myrcene, (5) α-phellandrene, (6) α-terpinene, (7) R-limonene, (8) γ-terpinene, (9) p-cymene, and (10) Camphene) spiked into a chamber-style impinger. The quantification of BVOCs was made by collection on multiple-bed sorbent tubes (STs) and subsequent analysis by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Using this approach, sub-ppb level mixtures of gaseous BVOCs were generated at different sweep cycles. The mean concentrations of 10 BVOCs generated from the most stable conditions (i.e., in the third sweep cycle) varied in the range of 0.37+/-0.05 to 7.27+/-0.86ppb depending on the initial concentration of liquid standard spiked into the system. The reproducibility of the gaseous BVOCs generated as mixture standards, if expressed in terms of relative standard error using the concentration datasets acquired under stable conditions, ranged from 1.64 (α-phellandrene) to 9.67% (R-limonene).

Optimization of a laser plasma x-ray source for ultrafast x-ray absorption spectroscopy

Iqbal, M.,Ijaz, M.,Noh, D. Y.,Janulewicz, K. A.,Stiel, H.,Nickles, P. V. 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. No.

<P>We present optimization of laser plasma x-ray experimental conditions for ultrafast x-ray absorption spectroscopy measurements on broad range of transition metal oxides. First, the x-ray flux generated from a laser plasma source was optimized with an emphasis on the Bremsstrahlung by investigating the influence of the angle of the incidence of laser beam on a Cu tape target. The x-ray flux emitted in both the front and transmitted side of the target was found to be optimal at the incident angle of 15 similar to 25 degrees. Moreover the manipulation of the Bremsstrahlung peak energy by the laser focus distribution was discussed. In addition to the source optimization, we present a scheme to find the time-delay zero position in a pump-probe experiment together with a normalization scheme for x-ray source fluctuations. As a feasibility check, we present the transmitted spectra of two materials, Ni and NiO.</P>

Influence of Zirconium Substitution on Dielectric, Ferroelectric and Field-induced Strain Behaviors of Lead-free 0.99[Bi1/2(Na0.82K0.18)1/2(Ti1−xZrx)O3]-0.01LiSbO3 Ceramics

A. Zaman,Y. Iqbal,A. Hussain,G. H. Ryu,송태권,M. H. Kim,W. J. Kim 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.5

The Crystal structure, dielectric, ferroelectric and field-induced strain behaviors of lead-free 0.99[Bi_1/2(Na_0.82K_0.18)_1/2(Ti_1−xZr_x)O₃]-0.01LiSbO₃ (BNKTZ-LS) ceramics were investigated in the composition range <i>x</i> = 0 - 0.040. XRD patterns revealed the formation of a pure perovskite phase with no apparent structural phase transition. The temperature-dependent dielectric peaks of the BNKTZ-LS ceramics broadened and the ferroelectric polarizations decreased with increasing Zr concentration. Ferroelectric and bipolar field induced-strain curves indicated a disruption of ferroelectric order upon Zr addition into the BNKT-LS ceramics. This destabilization of the ferroelectric order was accompanied by an enhanced field-induced strain. A high field-induced strain (<i>S</i> = 0.30%) with a normalized strain (<i>d^*₃₃</i> = <i>S_max</i>/<i>E_max</i> = 500 pm/V) was observed at an applied electric field of 6 kV/mm at x = 0.020.