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1,882 results on '"Shabbir, Muhammad A"'

15. Effect of Microwaves on Food Proteins

Author

Pratap-Singh, Anubhav, Shabbir, Muhammad Asim, Ahmed, Waqar, Barbosa-Cánovas, Gustavo V., Series Editor, Aguilera, José Miguel, Advisory Editor, Candoğan, Kezban, Advisory Editor, Hartel, Richard W., Advisory Editor, Peleg, Micha, Advisory Editor, Rahman, Shafiur, Advisory Editor, Rao, M. Anandha, Advisory Editor, Roos, Yrjö, Advisory Editor, Welti-Chanes, Jorge, Advisory Editor, Pratap Singh, Anubhav, editor, Erdogdu, Ferruh, editor, Wang, Shaojin, editor, and Ramaswamy, Hosahalli S., editor

Published
2024
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16. Spectrally Selective Thermal Emission from Graphene Decorated with Metallic Nanoparticles

Author

Craft, Jayden, Shabbir, Muhammad Waqas, Englund, Dirk R., Osgood III, Richard M., and Leuenberger, Michael N.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We showed in past work that nanopatterned monolayer graphene (NPG) enables spectrally selective thermal emission in the mid-infrared (mid-IR) from 3 to 12 $\mu$m. In that case the spectral selection is realized by means of the localized surface plasmon (LSP) resonances inside graphene. Here we show that graphene decorated with metallic nanoparticles, such as Ag nanocubes or nanospheres, also realize spectrally selective thermal emission, but in this case by means of acoustic graphene plasmons (AGPs) localized between graphene and the Ag nanoparticle inside a dielectric material. Our finite-difference time domain (FDTD) calculations show that the spectrally selective thermal radiation emission can be tuned by means of a gate voltage into two different wavelength regimes, namely the atmospherically opaque regime between $\lambda=5$ $\mu$m and $\lambda=8$ $\mu$m or the atmospherically transparent regime between $\lambda=8$ $\mu$m and $\lambda=12$ $\mu$m. This allows for electric switching between radiative heat trapping mode for the fomer regime and radiative cooling mode for the latter regime. Our theoretical results can be used to develop graphene-based thermal management systems for smart fabrics., Comment: 20 pages, 7 figures

Published
2022

19. Integrated track of nano-informatics coupling with the enrichment concept in developing a novel nanoparticle targeting ERK protein in Naegleria fowleri

Author

Naveed Muhammad, ul Ain Noor, Aziz Tariq, Saleem Ayesha, Shabbir Muhammad Aqib, Khan Ayaz Ali, and Albekairi Thamer H.

Subjects
primary amoebic meningoencephalitis, nonvehicle, nanoparticles, blood–brain barrier, Chemistry, QD1-999
Abstract

Naegleria fowleri is a free-living amoeba that causes primary amoebic meningoencephalitis. Despite combination drug therapies, N. fowleri is not sensitive to current drug therapies, contributing to the pathogen’s mortality rate of 98%. To enable rational drug designing, this study has proposed an integrated track of nanotechnology coupling with the enrichment concept. In the current study, zinc oxide nanoparticles (ZNP) were screened against ERK protein, which is responsible for the production of pro-inflammatory cytokines that cause brain disturbance in N. fowleri infection. Furthermore, an enrichment analysis has been executed to increase the efficiency of the ZNP through the addition of two amines and one chlorine group. The computational prediction of zeta potential, cytotoxicity, organ toxicity, calculations of binding free energy, and ADMET analysis shows that it is stable and possesses no toxic effect. Amine + chlorine enriched ZNP resulted in a binding energy of −7.8 kcal/mol, a zeta potential reliability of −40 mV, a cytotoxicity of −0.0002, inactive against all the targeted organ models, ADMET profiling shows a molecular weight of 320.54 g/mol, a lipophilicity of −0.99, high water solubility, and good gastrointestinal tract absorption. This proposed invention represents the future work for in vitro in combating this devastating disease toward a reliable therapeutic target with drugs that specifically aimed to inhibit the infection.

Published
2024
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29. Plasmonically enhanced tunable spectrally selective NIR and SWIR photodetector based on intercalation doped nanopatterned multilayer graphene

Author

Shabbir, Muhammad Waqas and Leuenberger, Michael N.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We present a proof of concept for a spectrally selective near-infrared (NIR) and short-wavelength infrared (SWIR) photodetector based on nanopatterned multilayer graphene intercalated with FeCl$_3$ (NPMLG-FeCl$_3$), enabling large modulation p-doping of graphene. The localized surface plasmons (LSPs) on the graphene sheets in NPMLG-FeCl$_3$ allow for electrostatic tuning of the photodetection in the NIR and SWIR regimes from $\lambda =1.3$ $\mu$m to 3 $\mu$m, which is out of range for nanopatterned monolayer graphene (NPG). Most importantly, the LSPs along with an optical cavity increase the absorbance from about $N\times 2.6$\% for $N$-layer graphene-FeCl$_3$ (without patterning) to nearly 100\% for NPMLG-FeCl$_3$, where the strong absorbance occurs locally inside the graphene sheets only. Our NIR and SWIR detection scheme relies on the photo-thermoelectric effect induced by asymmetric patterning of the multi-layer graphene (MLG) sheets. The LSPs on the nanopatterned side create hot carriers that give rise to Seebeck photodetection at room temperature achieving a responsivity of $R=6.15\times 10^3$ V/W, a detectivity of $D^*=2.3\times 10^{9}$ Jones, and an ultrafast response time of the order of 100 ns. Our theoretical results pave the way to graphene-based photodetection, optical IR communication, IR color displays, and IR spectroscopy in the NIR, SWIR, mid-wavelength infrared (MWIR), and long-wavelength infrared (LWIR) regimes., Comment: 8 pages, 6 figures

Published
2021

32. Oman's Ability to Attract FDI: Dunning Instrument Survey Analysis

Author

Sulaiman, Mohammed Ali Bait Ali, Rana, Seemab, and Shabbir, Muhammad Salman

Abstract

The purpose of this paper is to establish the extent to which Oman is capable of attracting more of the foreign direct investment (FDI) through dunning model instruments. The results of the analysis are determined using responses provided by the foreign companies concerning the features of Oman. Data used in the analysis were collected from 30 different foreign companies operating in Dhofar region of Oman using questionnaires. ANOVA test, Chi-square tests and Friedman's mean ranks were carried out to test the homogeneity and magnitude of the responses given by the respective companies. the findings of Effect size analysis indicate that Oman's system structure, Policy framework, provision of facilities and ease of access are strongly contributing in attracting FDI. However, Oman needs to focus on the improvement of business friendly environment and compassionate policy formation in favor of investors.

Published
2020

39. Benzimidazolium quaternary ammonium salts: synthesis, single crystal and Hirshfeld surface exploration supported by theoretical analysis

Author

Sajid Jamil, Humaira Yasmeen Gondal, Akbar Ali, Ajaz Hussain, Nadia Akram, Muhammad Nisar, Muhammad Nawaz Tahir, Muhammad Ashfaq, Abdul Rauf Raza, Shabbir Muhammad, Zain M. Cheema, Aleena Mustafai, and Manal Y. Sameeh

Subjects
benzimidazolium, quaternary ammonium salts, synthesis, single crystal and Hirshfeld surface, theoretical analysis, Science
Abstract

Owing to the broad applications of quaternary ammonium salts (QAS), we present the synthesis of benzimidazolium-based analogues with variation in the alkyl and alkoxy group at N-1 and N-3 positions. All the compounds were characterized by spectroscopic techniques and found stable to air and moisture both in the solid and solution state. Moreover, molecular structures were established through single-crystal X-ray diffraction studies. The crystal packing of the compounds was stabilized by numerous intermolecular interactions explored by Hirshfeld surface analysis. The enrichment ratio was calculated for the pairs of chemical species to acquire the highest propensity to form contacts. Void analysis was carried out to check the mechanical response of the compounds. Furthermore, theoretical investigations were also performed to explore the optoelectronic properties of compounds. Natural population analysis (NPA) has been conducted to evaluate the distribution of charges on the synthesized compounds, whereas high band gaps of the synthesized compounds by frontier molecular orbital (FMO) analysis indicated their stability. Nonlinear optical (NLO) analysis revealed that the synthesized QAS demonstrates significantly improved NLO behaviour than the standard urea.

Published
2024
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46. Plasmonically enhanced spectrally selective narrowband MWIR and LWIR light detection based on hybrid nanopatterned graphene and phase changing vanadium oxide heterostructure operating close to room temperature

Author

Shabbir, Muhammad Waqas, Chandra, Sayan, and Leuenberger, Michael N.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Optics
Abstract

We present the model of an ultrasensitive mid-infrared (mid-IR) photodetector operating in the mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) domains consisting of a hybrid heterostructure made of nanopatterned graphene (NPG) and vanadium dioxide (VO$_2$) which exhibits a large responsivity of $R\sim 10^4$ V/W, a detectivity exceeding $D^*\sim 10^{10}$ J, and a sensitivity in terms of noise-equivalent power $\mathrm{NEP}\sim 100$ fW/$\sqrt{\rm Hz}$ close to room temperature by taking advantage of the phase change of a thin VO$_2$ film. Our proposed photodetector can reach an absorption of nearly 100\% in monolayer graphene due to localized surface plasmons (LSPs) around the patterned circular holes. The geometry of the nanopattern and an electrostatic gate potential can be used to tune the absorption peak in the mid-IR regime between 3 and 12 $\mu$m. After the photon absorption by the NPG sheet and the resulting phase change of VO$_2$ from insulating to metallic phase the applied bias voltage $V_b$ triggers a current through the VO$_2$ sheet, which can be detected electronically in about 1 ms, shorter than the detection times of current VO$_2$ bolometers. Our envisioned mid-IR photodetector reaches detectivities of cryogenically cooled HgCdTe photodetectors and sensitivities larger than VO$_2$ microbolometers while operating close to room temperature., Comment: 8 pages, 9 figures

Published
2021

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