157 results on '"Gul Rahman"'
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2. Biomimetic Electrochemical Sensors Based on Core-Shell Imprinted Polymers for Targeted Sunset Yellow Estimation in Environmental Samples
- Author
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Sumeet Malik, Adnan Khan, Hamayun Khan, Gul Rahman, Nauman Ali, Sabir Khan, and Maria Del Pilar Taboada Sotomayor
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adsorption ,electrochemical sensors ,molecularly imprinted polymers ,precipitation polymerization ,sunset yellow dye ,Biotechnology ,TP248.13-248.65 - Abstract
Magnetic molecularly imprinted polymers (MMIPs) contain the predesigned specialized recognition capability that can be chosen to build credible functional materials, that are easy to handle and have a good degree of specificity. Hence, the given piece of work is intended to design a novel electrochemical sensor incorporating magnetite-based molecularly imprinted polymers. The building materials consisted of a cross-linker (EGDMA), reaction-initiator (AIBN), monomer (methylene succinic acid-MSA), and template molecule (Sunset Yellow-SY dye). MMIPs exhibited a diameter of 57 nm with an irregular shape due to the presence of cavities based on SEM analysis. XRD patterns exhibited crystallinity, as well as amorphous peaks that are attributed to polymeric and non-polymeric frameworks of MMIPs. The crystallite size of the MMIPs from XRD analysis was found to be 16.28 nm based on the Debye-Scherrer’s equation. Meanwhile, the FTIR bands showed the synthesis of MMIPs using monomer and methylene succinic acid. The sorption data at the optimized operating conditions (pH 2, sorbent dosage 3 mg, time 18 min) showed the highest sorption capacity of 40 mg/g. The obtained data best fitted to the Langmuir sorption isotherm and followed the pseudo-second-order kinetics. The magneto-sensors were applied for ultrasensitive, rapid, and simple sensing of SY dye. The electrochemical experiments were run at the operating condition range of (scan rate 10–50 mV/s, tads 0–120 s, pH 5–9, potential range 1–1.5 V for CV and 1–1.3 V for SWAdASV). The linear range of detection was set to 1.51 × 10−6 M to 1.51 × 10−6 M posing LOD and LOQ values of 8.6242 × 10−5 M and 0.0002874 M, respectively. The regression analysis value for the calibration was found to be 0.950. Additionally, high adsorption efficiency, selectivity, reusability, and strong structural stability of the magneto-sensors showed potential use for SY detection in real samples. These characteristics make MMIPs a viable electrochemical substrate for the detection of chemical contaminants in the environment and in health-related products.
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- 2023
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3. Tuning the optoelectronic properties of hematite with rhodium doping for photoelectrochemical water splitting using density functional theory approach
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Abdur Rauf, Muhammad Adil, Shabeer Ahmad Mian, Gul Rahman, Ejaz Ahmed, Zia Mohy Ud Din, and Wei Qun
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Medicine ,Science - Abstract
Abstract Hematite (Fe2O3) is one of the best candidates for photoelectrochemical water splitting due to its abundance and suitable bandgap. However, its efficiency is mostly impeded due to the intrinsically low conductivity and poor light absorption. In this study, we targeted this intrinsic behavior to investigate the thermodynamic stability, photoconductivity and optical properties of rhodium doped hematite using density functional theory. The calculated formation energy of pristine and rhodium doped hematite was − 4.47 eV and − 5.34 eV respectively, suggesting that the doped material is thermodynamically more stable. The DFT results established that the bandgap of doped hematite narrowed down to the lower edge (1.61 eV) in the visible region which enhanced the optical absorption and photoconductivity of the material. Moreover, doped hematite has the ability to absorb a broad spectrum (250–800) nm. The enhanced optical absorption boosted the photocurrent and incident photon to current efficiency. The calculated results also showed that the incorporation of rhodium in hematite induced a redshift in optical properties.
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- 2021
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4. Investigation of Alumina-Doped Prunus domestica Gum Grafted Polyaniline Epoxy Resin for Corrosion Protection Coatings for Mild Steel and Stainless Steel
- Author
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Muhammad Kamran, Anwar ul Haq Ali Shah, Gul Rahman, Salma Bilal, and Philipp Röse
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PANI composite ,corrosion protection ,mild steel ,Tafel analysis ,epoxy resin ,PDG ,Organic chemistry ,QD241-441 - Abstract
Eco-friendly inhibitors have attracted considerable interest due to the increasing environmental issues caused by the extensive use of hazardous corrosion inhibitors. In this paper, environmentally friendly PDG-g-PANI/Al2O3 composites were prepared by a low-cost inverse emulsion polymerization for corrosion inhibition of mild steel (MS) and stainless steel (SS). The PDG-g-PANI/Al2O3 composites were characterized by different techniques such as X-ray diffraction (XRD), UV/Vis, and FTIR spectroscopy. XRD measurements show that the PDG-g-PANI/Al2O3 composite is mostly amorphous and scanning electron micrographs (SEM) reveal a uniform distribution of Al2O3 on the surface of the PDG-g-PANI matrix. The composite was applied as a corrosion inhibitor on mild steel (MS) and stainless steel (SS), and its efficiency was investigated by potentiodynamic polarization measurement in a 3.5% NaCl and 1 M H2SO4 solution. Corrosion kinetic parameters obtained from Tafel evaluation show that the PDG-g-PANI/Al2O3 composites protect the surface of MS and SS with inhibition efficiencies of 92.3% and 51.9% in 3.5% NaCl solution, which is notably higher than those obtained with untreated epoxy resin (89.3% and 99.5%). In particular, the mixture of epoxy/PDG-g-PANI/Al2O3 shows the best performance with an inhibition efficiency up to 99.9% on MS and SS. An equivalent good inhibition efficiency was obtained for the composite for 1M H2SO4. Analysis of activation energy, formation enthalpy, and entropy values suggest that the epoxy/PDG-g-PANI/Al2O3 coating is thermodynamically favorable for corrosion protection of MS and exhibits long-lasting stability.
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- 2022
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5. Potential Impacts of Prunus domestica Based Natural Gum on Physicochemical Properties of Polyaniline for Corrosion Inhibition of Mild and Stainless Steel
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Muhammad Kamran, Anwar ul Haq Ali Shah, Gul Rahman, and Salma Bilal
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Prunus domestica gum (PDG) ,PANI ,composites ,corrosion protection ,Organic chemistry ,QD241-441 - Abstract
The lack of an eco-friendly approach towards application of polyaniline as a coating material has been one of the most challenging tasks. Herein, the synthesis of green Prunus domestica gum grafted polyaniline (PDG-g-PANI) composite is reported by a cost-effective emulsion polymerization for application as an efficient anti-corrosion material for mild steel (MS) and stainless steel (SS) in a strong corroding environment. The composite formation was confirmed by Ultraviolet Visible (UV-Visible) and Fourier Transformed Infrared (FTIR) spectroscopies. X-ray diffraction data revealed the amorphous nature of the PDG-g-PANI. Scanning Electron Microscopic (SEM) images showed a bi-layered structure having a parent porous layer of PANI coated with afibrous layer of PDG. The solubility test confirmed the dissolution of PDG-g-PANI in common organic solvents such as acetone, ethanol, propanol, butanol, chloroform, N-Methyl-2-pyrrolidone, dimethyl sulfoxide, and the mixture of propanol and chloroform. The polarization curve, open circuit potential, electrochemical impendence spectroscopy (EIS), and gravimetric analysis were applied to investigate the corrosion protection behavior of the composite on MS and SS in 3.5% NaCl and 1 M H2SO4 solution. The PDG-g-PANI-coated MS exhibited 96% corrosion inhibition efficiency as compared to 86% and 43% for pristine PANI and PDG in 3.5% NaCl solution while PDG-g-PANI-coated SS showed 98% corrosion inhibition efficiency. Moreover, 99% and 96.6% corrosion protection was observed for PDG-g-PANI-coated MS and SS in 1 M H2SO4 solution. Gravimetric studies revealed that PDG-g-PANI coating can protect MS up to 93% for 14 days in salt solution while 97% corrosion inhibition efficiency was retained for 2 months in open air.
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- 2022
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6. Performance Improvement of Gold Electrode towards Methanol Electrooxidation in Akaline Medium: Enhanced Current Density Achieved with Poly(aniline-co-2-hydroxyaniline) Coating at Low Overpotential
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Anwar ul Haq Ali Shah, Sadaf Zia, Gul Rahman, and Salma Bilal
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poly(aniline-co-2-hydroxyaniline) ,electrochemistry ,electrooxidation ,alkaline fuel cell ,Organic chemistry ,QD241-441 - Abstract
Electronically conducting poly (aniline-co-2-hydroxyaniline) (PACHA), a copolymer of aniline and 2-hydroxyaniline (2HA), was electrochemically coated on gold substrate for methanol electrooxidation in alkaline media. The electrochemical behavior of PACHA coated gold electrode towards methanol electrooxidation was investigated via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) for application in an alkaline fuel cell. Methanol electrooxidation was observed at two different electrode potentials depending on the concentration of the base. At the PACHA coated gold electrode, the methanol oxidation peak was observed at lower overpotential (at 0.19 V) in a solution of high base concentration (1.8 M NaOH), which was 30 mV lower than the peak for the uncoated gold electrode. In addition, the Faradic current Imax obtained on the PACHA coated electrode (20 mA) was two times higher as compared to the Faradic current Imax of the un-modified gold electrode (10 mA). In solution of lower base concentration (0.06 M NaOH), the electrooxidation of methanol became sluggish on both electrodes, as indicated by peak shifting towards positive potential and with reduced faradaic current (at 0.74 V on PACHA coated electrode; Imax 10 mA). The electrooxidation of methanol at both lower and higher electrode potentials was analyzed mechanistically and discussed in light of the literature. EIS results were interpreted using Nyquist and Bode plots. The charge transfer resistance was decreased and pseudo-capacitive behavior changed to conductive behavior when external applied potential was increased from 0.1 V to 0.4 V.
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- 2022
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7. Reduced Graphene Oxide/Poly(Pyrrole-co-Thiophene) Hybrid Composite Materials: Synthesis, Characterization, and Supercapacitive Properties
- Author
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Anwar ul Haq Ali Shah, Sami Ullah, Salma Bilal, Gul Rahman, and Humaira Seema
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reduced graphene oxide (RGO) ,poly(pyrrole-co-thiophene) (COP) ,supercapacitor ,energy density ,power density ,Organic chemistry ,QD241-441 - Abstract
Reduced graphene oxide/poly(pyrrol-co-thiophene) (RGO/COP), prepared by facile in-situ oxidative copolymerization, is reported as a new hybrid composite material with improved supercapacitance performance as compared to the respective homopolymers and their composites with RGO. The as-prepared hybrid materials were characterized with ultraviolet–visible (UV–Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis. The electrochemical behavior and energy storage properties of the materials were tested by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrostatic impedance spectroscopy (EIS) techniques in 0.5 M H2SO4. The specific capacitance (Csp) for RGO/COP calculated from the CV curve was 467 F/g at a scan rate of 10 mV/s. While the Csp calculated from the GCD was 417 F/g at a current density of 0.81 A/g. The energy density calculated was 86.4 Wh/kg with a power density of 630 W/kg. The hybrid composite exhibits good cyclic stability with 65% capacitance retention after 1000 cycles at a scan rate of 100 mV/s. The present work brings a significance development of RGO/COP composites to the electrode materials for pseudocapacitive application.
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- 2020
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8. Basic Blue Dye Adsorption from Water Using Polyaniline/Magnetite (Fe3O4) Composites: Kinetic and Thermodynamic Aspects
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Amir Muhammad, Anwar-ul-Haq Ali Shah, Salma Bilal, and Gul Rahman
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Basic Blue 3 dye (BB3), polyaniline/Fe3O4 composite ,Freundlich ,Langmuir ,Tempkin and Dubbanin-Radushkavitch adsorption isotherm ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
Owing to its exciting physicochemical properties and doping−dedoping chemistry, polyaniline (PANI) has emerged as a potential adsorbent for removal of dyes and heavy metals from aqueous solution. Herein, we report on the synthesis of PANI composites with magnetic oxide (Fe3O4) for efficient removal of Basic Blue 3 (BB3) dye from aqueous solution. PANI, Fe3O4, and their composites were characterized with several techniques and subsequently applied for adsorption of BB3. Effect of contact time, initial concentration of dye, pH, and ionic strength on adsorption behavior were systematically investigated. The data obtained were fitted into Langmuir, Frundlich, Dubbanin-Rudiskavich (D-R), and Tempkin adsorption isotherm models for evaluation of adsorption parameters. Langmuir isotherm fits closely to the adsorption data with R2 values of 0.9788, 0.9849, and 0.9985 for Fe3O4, PANI, and PANI/Fe3O4 composites, respectively. The maximum amount of dye adsorbed was 7.474, 47.977, and 78.13 mg/g for Fe3O4, PANI, and PANI/Fe3O4 composites, respectively. The enhanced adsorption capability of the composites is attributed to increase in surface area and pore volume of the hybrid materials. The adsorption followed pseudo second order kinetics with R2 values of 0.873, 0.979, and 0.999 for Fe3O4, PANI, and PANI/Fe3O4 composites, respectively. The activation energy, enthalpy, Gibbs free energy changes, and entropy changes were found to be 11.14, −32.84, −04.05, and −0.095 kJ/mol for Fe3O4, 11.97, −62.93, −07.78, and −0.18 kJ/mol for PANI and 09.94, −74.26, −10.63, and −0.210 kJ/mol for PANI/Fe3O4 respectively, which indicate the spontaneous and exothermic nature of the adsorption process.
- Published
- 2019
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9. An Overview of the Recent Progress in the Synthesis and Applications of Carbon Nanotubes
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Gul Rahman, Zainab Najaf, Asad Mehmood, Salma Bilal, Anwar ul Haq Ali Shah, Shabeer Ahmad Mian, and Gulam Ali
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carbon nanotubes ,synthesis routes ,biomedical applications ,energy storage and conversion ,electronic devices ,Organic chemistry ,QD241-441 - Abstract
Carbon nanotubes (CNTs) are known as nano-architectured allotropes of carbon, having graphene sheets that are wrapped forming a cylindrical shape. Rolling of graphene sheets in different ways makes CNTs either metals or narrow-band semiconductors. Over the years, researchers have devoted much attention to understanding the intriguing properties CNTs. They exhibit some unusual properties like a high degree of stiffness, a large length-to-diameter ratio, and exceptional resilience, and for this reason, they are used in a variety of applications. These properties can be manipulated by controlling the diameter, chirality, wall nature, and length of CNTs which are in turn, synthesis procedure-dependent. In this review article, various synthesis methods for the production of CNTs are thoroughly elaborated. Several characterization methods are also described in the paper. The applications of CNTs in various technologically important fields are discussed in detail. Finally, future prospects of CNTs are outlined in view of their commercial applications.
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- 2019
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10. 193 A rare cause of small bowel obstruction- Obturator Hernia
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Loganathan, Santhosh, primary, Gul, Rahman, additional, and Ahmed, Tarig, additional
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- 2023
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11. Recent Development of Nanostructured Nickel Metal-Based Electrocatalysts for Hydrogen Evolution Reaction: A Review
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Noureen Amir Khan, Gul Rahman, Tung M. Nguyen, Anwar Ul Haq Ali Shah, Cham Q. Pham, Minh Xuan Tran, and Dang Le Tri Nguyen
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General Chemistry ,Catalysis - Published
- 2022
12. Pre-Service Mathematics Teachers’ Experience with Productive Struggle
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Zareen Gul Rahman
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Education - Published
- 2022
13. Spatio-temporal change in the glaciers of Astore Basin (North-Western Himalaya), between 2016 and 2021 by using Sentinel-2 satellite data
- Author
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gul, rahman, primary, Khan, Saad, additional, Ullah, Rehman, additional, Bibi, Sidra, additional, and Ali, Muhammad, additional
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- 2023
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14. An amphiphilic polyoxometalate–CNT nanohybrid as a highly efficient enzyme-free electrocatalyst for H2O2 sensing
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Eman Gul, Gul Rahman, Yuefeng Wu, Tanveer Hussain Bokhari, Ata ur Rahman, Amina Zafar, Zohaib Rana, Attaullah Shah, Shafqat Hussain, Khan Maaz, Shafqat Karim, Saqib Javaid, Hongyu Sun, Mashkoor Ahmad, Guolei Xiang, and Amjad Nisar
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Materials Chemistry ,General Chemistry ,Catalysis - Abstract
A highly active electrochemical amphiphilic POM–CNT nanohybrid using non-covalent interactions for highly efficient detection of H2O2 is reported. The synergy between POMs and CNTs results in 10 times higher current response than pristine POM.
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- 2022
15. Stimulated reversal of the strong adhesion of catechol onto a silica surface
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Muhammad Ilyas, Shabeer Ahmad Mian, Abdur Rauf, Ejaz Ahmed, Gul Rahman, Arindam Sannyal, and Joonkyung Jang
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General Chemistry - Published
- 2021
16. Investigation of Alumina-Doped Prunus domestica Gum Grafted Polyaniline Epoxy Resin for Corrosion Protection Coatings for Mild Steel and Stainless Steel
- Author
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Röse, Muhammad Kamran, Anwar ul Haq Ali Shah, Gul Rahman, Salma Bilal, and Philipp
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PANI composite ,corrosion protection ,mild steel ,Tafel analysis ,epoxy resin ,PDG ,Al2O3 ,corrosion inhibition efficiency - Abstract
Eco-friendly inhibitors have attracted considerable interest due to the increasing environmental issues caused by the extensive use of hazardous corrosion inhibitors. In this paper, environmentally friendly PDG-g-PANI/Al2O3 composites were prepared by a low-cost inverse emulsion polymerization for corrosion inhibition of mild steel (MS) and stainless steel (SS). The PDG-g-PANI/Al2O3 composites were characterized by different techniques such as X-ray diffraction (XRD), UV/Vis, and FTIR spectroscopy. XRD measurements show that the PDG-g-PANI/Al2O3 composite is mostly amorphous and scanning electron micrographs (SEM) reveal a uniform distribution of Al2O3 on the surface of the PDG-g-PANI matrix. The composite was applied as a corrosion inhibitor on mild steel (MS) and stainless steel (SS), and its efficiency was investigated by potentiodynamic polarization measurement in a 3.5% NaCl and 1 M H2SO4 solution. Corrosion kinetic parameters obtained from Tafel evaluation show that the PDG-g-PANI/Al2O3 composites protect the surface of MS and SS with inhibition efficiencies of 92.3% and 51.9% in 3.5% NaCl solution, which is notably higher than those obtained with untreated epoxy resin (89.3% and 99.5%). In particular, the mixture of epoxy/PDG-g-PANI/Al2O3 shows the best performance with an inhibition efficiency up to 99.9% on MS and SS. An equivalent good inhibition efficiency was obtained for the composite for 1M H2SO4. Analysis of activation energy, formation enthalpy, and entropy values suggest that the epoxy/PDG-g-PANI/Al2O3 coating is thermodynamically favorable for corrosion protection of MS and exhibits long-lasting stability.
- Published
- 2022
- Full Text
- View/download PDF
17. Rational Design of Broadly Absorbing Boron Dipyrromethene-Carbazole Dyads for Dye-Sensitized Solar Cells: A DFT Study
- Author
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Muhammad Yaseen, Gul Rahman, Muhammad Bilal Khan, and Ata Ur Rahman
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Materials science ,Band gap ,Carbazole ,General Chemical Engineering ,Phosphole ,General Chemistry ,Photochemistry ,Article ,Dye-sensitized solar cell ,chemistry.chemical_compound ,Chemistry ,chemistry ,Moiety ,Density functional theory ,BODIPY ,HOMO/LUMO ,QD1-999 - Abstract
Structure engineering of boron dipyrromethene (BODIPY) organic dye, to increase its light-harvesting efficiency in dye-sensitized solar cells, has been the subject of rigorous research recently. Herein, we report on the rational designing of BODIPY-carbazole (D-π-A-A) dyads using density functional theory (DFT). The structure of BODIPY-carbazole was first modified by substituting an electron-donating −N(CH3)2 group at the electron-rich carbazole moiety, and two electron-accepting −COOH groups at the BODIPY core. The DFT calculations showed a significant lowering of the band gap from 2.9 eV (pristine BODIPY-carbazole dyad) to 1.87 eV (modified BODIPY-carbazole dyad). Further modification was demonstrated by the incorporation of heterocyclic rings such as thiophene (denoted as D1T), furan (D1F), and phosphole (D1P) into BODIPY-carbazole moiety, which red-shifted the light absorption spectra and consequently improved the light-harvesting efficiency of the dyes. The interactions at the dye/semiconductor interface were studied by employing their bridged-bidentate adsorption models over the titanium dioxide (TiO2)38 nanocluster. Results suggested that the electrons can be efficiently injected from the lowest unoccupied molecular orbital (LUMO) of dyes into the conduction band of TiO2. Among the three dyads, D1P exhibited superior photovoltaic performance with a maximum power conversion efficiency of 13.50%, a short-circuit current density (Jsc) of 27.2 mA·cm–2, and an open-circuit voltage (Voc) of 731 mV. The structurally configured new D1P dye can be used as a potential alternative photosensitizer for high-performance dye-sensitized solar cells.
- Published
- 2021
18. EP-53 The ambulatory care of unusual presentation of Boerhaave's syndrome
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Loganathan, Santhosh, primary, Gul, Rahman, additional, and Whittaker, Laura, additional
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- 2022
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19. EP-186 Recurrent Boerhaave's Syndrome
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Loganathan, Santhosh, primary, Gul, Rahman, additional, and Whittaker, Laura, additional
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- 2022
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20. Challenges in Improving Performance of Oxide Thermoelectrics Using Defect Engineering
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Jamil Ur Rahman, Gul Rahman, and Soonil Lee
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Materials science ,InformationSystems_INFORMATIONSTORAGEANDRETRIEVAL ,Oxide ,Defect engineering ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Thermoelectric materials ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,0210 nano-technology ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) - Abstract
Oxide thermoelectric materials are considered promising for high-temperature thermoelectric applications in terms of low cost, temperature stability, reversible reaction, and so on. Oxide materials have been intensively studied to suppress the defects and electronic charge carriers for many electronic device applications, but the studies with a high concentration of defects are limited. It desires to improve thermoelectric performance by enhancing its charge transport and lowering its lattice thermal conductivity. For this purpose, here, we modified the stoichiometry of cation and anion vacancies in two different systems to regulate the carrier concentration and explored their thermoelectric properties. Both cation and anion vacancies act as a donor of charge carriers and act as phonon scattering centers, decoupling the electrical conductivity and thermal conductivity.
- Published
- 2022
21. Template-Free Hydrothermal Growth of Nickel Sulfide Nanorods as High-Performance Electroactive Materials for Oxygen Evolution Reaction and Supercapacitors
- Author
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Anwar ul Haq Ali Shah, Oh-Shim Joo, Adeel Mehmood, Gul Rahman, and Shabeer Ahmad Mian
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Supercapacitor ,Nickel sulfide ,Materials science ,General Chemical Engineering ,Oxygen evolution ,Energy Engineering and Power Technology ,Substrate (chemistry) ,Precious metal ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Hydrothermal circulation ,chemistry.chemical_compound ,Fuel Technology ,020401 chemical engineering ,chemistry ,Chemical engineering ,Energy transformation ,Nanorod ,0204 chemical engineering ,0210 nano-technology - Abstract
Transition-metal sulfides with nanostructured features grown on a conductive substrate have been suggested as a promising alternative to precious metal-based electrocatalysts for energy conversion ...
- Published
- 2021
22. Synthesis of graphene nanoplatelets/polythiophene as a high performance supercapacitor electrode material
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Javed Iqbal, Ata Ur Rahman, Zeeshan Nawaz, Muhammad Yaseen, Hamsa Noreen, and Gul Rahman
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Supercapacitor ,chemistry.chemical_compound ,Electrode material ,Exfoliated graphite nano-platelets ,chemistry ,Materials Chemistry ,Polythiophene ,Nanotechnology ,General Chemistry ,Catalysis - Abstract
The preparation of a stable, efficient, inexpensive and high capacitance electrode material for supercapacitors is posing great challenges for researchers.
- Published
- 2021
23. Core-shell magnetic molecularly imprinted polymer for selective recognition and detection of sunset yellow in aqueous environment and real samples
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Sumeet Malik, Adnan Khan, Gul Rahman, Nauman Ali, Hamayun Khan, Sabir Khan, Maria D.P.T. Sotomayor, University of Peshawar, Islamia College University, National University of Engineering, and Universidade Estadual Paulista (UNESP)
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Real samples ,Sorbent ,Polymers ,Magnetic Phenomena ,MMIP ,Biochemistry ,Sunset yellow ,Molecular Imprinting ,Molecularly Imprinted Polymers ,Environmental samples ,Electrochemical/biomimetic sensor ,Adsorption ,Azo Compounds ,General Environmental Science - Abstract
Made available in DSpace on 2022-04-29T08:46:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-09-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Magnetic Molecularly imprinted polymers (MMIPs) have been recently recognized as an exceptional tool for monitoring and decontamination of environmental and biological samples of diverse nature. Based on the potential applications as sorbents and biomimetic sensors, herein, a core-shell magnetic-molecularly imprinted polymer (MMIP) was developed as a selective material for separation and sensing of sunset yellow (SY) dye in an aqueous environment and real samples. The MMIP was synthesized via precipitation polymerization using SY as a template, MAA as a functional monomer (chosen based on simulation studies), EGDMA as a cross-linking agent, and AIBN as an initiator. To elaborate the specificity of MMIP, a comparative agent, magnetic non-imprinted polymer (MNIP) was also synthesized. The XRD results showed that the MMIP showed both crystalline and amorphous structure attributed to the presence and polymeric and non-polymeric groups. The FTIR spectra confirmed synthesis of intermediate and final MMIP product. The SEM results showed spherical morphology and porous structure of the MMIP with an average particle size of 0.636 μm in diameter. The MMIP was first employed as a sorbent for the removal of SY from the aqueous environment. The binding experiments performed at optimized operating conditions (pH 2; time 30 min; sorbent dosage 3 mg; sorbate concentration 80 ppm) showed more selectivity when compared with MNIP. The data fitted best to Langmuir's sorption isotherm (Qo 359.8 mg/g) and followed the pseudo-second-order kinetic model. The synthesized MMIP was also used as an electrochemical sensor for detection of SY dye in the aqueous environment, which exhibited a linear range of detection as (1.51 × 10−6 – 1.5 × 10−3 M). The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.00413 M and 0.0137 M, respectively. While the R2 value was found to be 0.997 at optimized analytical conditions. These results suggested that the synthesized MMIP can be applied for the selective separation and quantification of SY dye in sample of diverse nature. Institute of Chemical Sciences University of Peshawar, Khyber Pakhtunkhwa Department of Chemistry Islamia College University, KP Laboratory of Physical Chemistry Research Faculty of Sciences National University of Engineering, Av. Tupac Amaru 210, Rimac Institute of Chemistry São Paulo State University (UNESP) and National Institute of Alternative Technologies for Detection Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM), SP Institute of Chemistry São Paulo State University (UNESP) and National Institute of Alternative Technologies for Detection Toxicological Evaluation and Removal of Micropollutants and Radioactives (INCT-DATREM), SP FAPESP: 2019/00677-7
- Published
- 2022
24. Developed meloxicam loaded microparticles for colon targeted delivery: Statistical optimization, physicochemical characterization, and in-vivo toxicity study
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Wasay, Syed Abdul, primary, Jan, Syed Umer, additional, Akhtar, Muhammad, additional, Noreen, Sobia, additional, and Gul, Rahman, additional
- Published
- 2022
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25. In‐situ formation of an efficient trimetallic ( <scp>Cu</scp> <scp>Zn</scp> <scp>Ag</scp> ) electrocatalyst for water oxidation
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Gul Rahman, HyukSu Han, Muhammad Akbar, Afzal Shah, Ghulam Ali, and Faiza Jan Iftikhar
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In situ ,Fuel Technology ,Materials science ,Nuclear Energy and Engineering ,Renewable Energy, Sustainability and the Environment ,Inorganic chemistry ,Energy Engineering and Power Technology ,Overpotential ,Electrocatalyst ,Current density - Published
- 2020
26. On 3‑total Edge Product Cordial Labelling of Octagonal Plane Map
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Rizwan Ullah, Gul Rahman, Tania Bibi, Muhammad Numan, and Andrea Semaničová-Fenovčíková
- Published
- 2021
27. Intersection Performance Using Computer Simulation Sidra Program for Traffic Flow in Shaheed Intersection Kabul Afghanistan
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Rustam Hafizyar, Gul Rahman Abdulrahimzai, Sayed Dawood Karimi, Mohammad Ali Mosaberpanah, Akbar Jan Polad, and Mozhdah Hafizyar
- Published
- 2021
28. Investigation of room-temperature ferromagnetism in $$\hbox {SrTiO}_3$$ perovskite structure via substitutional doping
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Sajjad Ali, Altaf Ur Rahman, A. Dahshan, Gul Rahman, Adeel Ahmed Awan, and S. S. Hayat
- Subjects
Fluid Flow and Transfer Processes ,Materials science ,Condensed matter physics ,Spintronics ,Magnetic moment ,Band gap ,Magnetism ,General Physics and Astronomy ,Condensed Matter::Materials Science ,Ferromagnetism ,Atom ,Curie temperature ,Condensed Matter::Strongly Correlated Electrons ,Density functional theory - Abstract
The C and N atomic doping and co-doping at all possible lattice sites in (STO) perovskite crystal structure have been investigated using density functional theory (DFT) calculations. Calculated formation energies indicate that C and N doping at O site in STO is more stable than at Sr site and Ti site. C incorporation at anion site significantly affects the electronic bandgap of STO by inducing spin-polarized defect states in bandgap region. Consequently transforming the non-magnetic STO to a magnetic with a magnetic moment of 2.0 per C atom and reduced the direct (indirect) bandgap 0.86 eV (0.18 eV) for spin-up (spin-down) channel, respectively. Further, with an increase of C atom concentration the magnetic moment of 2.0 per C atom remains constant, and also, half-metallicity is observed due to spin-down channel. Similarly, N atom substitution at anion site in STO crystal structure induces magnetism of 1.0 . N causes defect states due to which the bandgap of the spin-up channel decreased to 1.68 eV and shows half-metallicity due to the spin-down channel. We found that further increasing the N atom concentration enhanced the half-metallicity by increasing the number of states of the spin-down channel at Fermi energy. Finally, we studied the FM and AFM alignment of the magnetic moments at the dopants C, N and their co-doping in STO with different distances. We found that the C atom prefers AFM states, while the N atom prefers FM states. The calculated Curie temperature for two N atoms at near and far dopants is 722.16 K and 860.91 K, respectively. The results of tailored electronic and magnetic properties above room temperature are interesting from a theoretical perspective and may open opportunities for STO in electronic and spintronic devices.
- Published
- 2021
29. Formulation and Evaluation of Bisoprolol Hemifumarate Emulgel for Transdermal Drug Delivery
- Author
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Gul, Rahman, primary, Khan, Yasmin, additional, and Aman, Tajala, additional
- Published
- 2022
- Full Text
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30. Intersection Performance Using Computer Simulation Sidra Program for Traffic Flow in Shaheed Intersection Kabul Afghanistan
- Author
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Hafizyar, Rustam, primary, Abdulrahimzai, Gul Rahman, additional, Karimi, Sayed Dawood, additional, Mosaberpanah, Mohammad Ali, additional, Polad, Akbar Jan, additional, and Hafizyar, Mozhdah, additional
- Published
- 2021
- Full Text
- View/download PDF
31. Challenges and innovative strategies related to synthesis and electrocatalytic/energy storage applications of metal sulfides and its derivatives
- Author
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Saraf Khan, Asim Mahmood, Anwar Ul Haq Ali Shah, Gul Rahman, Adnan Khan, and Nabi Ullah
- Subjects
General Chemical Engineering ,Electrochemistry ,Analytical Chemistry - Published
- 2022
32. Formulation and evaluation of an ointment from Pinus gerardiana extracts indigenous to Balochistan.
- Author
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Shahwani, Ghulam Mustafa, Jan, Syed Umer, Akhtar, Muhammad, Razzaque, Ghulam, Gul, Rahman, Ul Haq, Noman, Arsalan, Muhammad, Wahid, Abdul, Farooq, Ghulam, and Qadir, Abdul
- Abstract
In skin disorders such as microbial and fungal infections, plants and their parts are used. However, there have been very few scientific reports of herbal extracts of the plant Pinus gerardiana to be administered transdermally. The antifungal activity was assessed using poisoned food method against the strains of three pathogenic fungi, namely Alternaria alternata, Curvularia lunata and Bipolaris specifera. Ointment was prepared according to British pharmacopeia and physiochemical evaluation tests were performed. The GCMS was used to determine the chemical composition of the essential oil of Pinus gerardiana. 27 components were obtained. Monoterpenes= 89.97%, Oxygenated monoterpenes = 8.75%, Sesquiterpenes = 2.21% out of 100% of the total composition. The extract of pinus gerardiana showed a zone of inhibition on organism Bipolaris specifera 2.98±0.1µg/ml, Alternaria alternate 3.48±0.21µ/ml and Curvularia lunata 5.04±0.24µg/ml. Ointment was prepared with pH 5.9, conductivity 0.1, viscosity 22.24 and tested for stability. Franz cells were used in vitro, and release was determined from 30 minutes to 12 hours. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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33. Formulation and assessment of controlled release tablets of famotidine by using eudragit RL 100 polymer.
- Author
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Rabani, Tehmina, Jan, Syed Umer, Razaque, Ghulam, Gul, Rahman, Khan, Kamran Ahmad, Rashid, Faisal, and Tufail, Muhammad
- Abstract
Controlled release" in drug release kinetics denotes reproducibility and predictability, implying that drug release from delivery devices follows a kinetically predictable and repeatable rate profile from dose to dose. In the current study controlled release tablets of famotidine were prepared by direct compression technique using Eudragit RL 100 polymer. Four different formulations of controlled release tablets of famotidine as (F1, F2, F3 and F4) were prepared by adding different drug to polymer ratio. The pre compression and the post compression of the formulation, characteristics were compared. All results obtained were within the specified standard limits. FTIR studies showed that both the drug and the polymer were compatible. In vitro dissolution study were conducted by Method II (Paddle Method) in phosphate buffer (pH 7.4), at 100rpm. Power law kinetic model was applied for drug release mechanism. The difference similarity of the dissolution profile was determined. The formulation F1 and F2 were released 97 and 96 % in 24 hours and other formulations F3 and F4 were released subsequently 93% and 90% in 24 hours. The results showed that incorporation of Eudragit RL 100 in the formulation of controlled release tablets prolong the drug release rates for 24 hours. The release mechanism was Non-Fickian diffusion mechanism. It was deducted from the current study that the Eudragit RL 100 can be efficiently incorporated in the formulation of controlled release dosage forms with predictable kinetics. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
34. Thermoelectric properties of KCaF3
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Asad Ali, Altaf Ur Rahman, and Gul Rahman
- Subjects
010302 applied physics ,Materials science ,Condensed matter physics ,02 engineering and technology ,Electron ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Thermoelectric materials ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Effective mass (solid-state physics) ,Seebeck coefficient ,0103 physical sciences ,Thermoelectric effect ,Figure of merit ,Density functional theory ,Charge carrier ,Electrical and Electronic Engineering ,0210 nano-technology - Abstract
Using first-principles calculations based on density functional theory (DFT) with generalized gradient approximation (GGA), the electronic and thermoelectric properties of KCaF3 are calculated. The electronic structure calculated with GGA shows that KCaF3 is an insulator. The thermoelectric properties of KCaF3 are computed as a function of chemical potential μ and charge carrier concentrations (1018–1022 cm−3). Both hole and electron doping decrease the absolute value of Seebeck coefficient. The calculated power factor shows that p-type KCaF3 has a larger power factor at the optimized charge carriers. The maximum figure of merit (ZT) occurs around 1021 cm−3 hole carrier concentrations and the largest value of ZT ∼0.7 is achieved at 800 K. When KCaF3 is doped with electron, the maximum ZT occurs around 1020 cm−3 and the largest value of ZT at 800 K is about 0.4. Hence, high ZT in KCaF3 is possible at high hole carrier concentrations as compared with electron carrier concentrations. Compared with n-type KCaF3, p-type KCaF3 has good thermoelectric properties, which are attributed to larger effective mass and low thermal conductivity of holes.
- Published
- 2019
35. Elucidation of the structural and charge separation properties of titanium-doped hematite films deposited by electrospray method for photoelectrochemical water oxidation
- Author
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Sang Youn Chae, Oh-Shim Joo, and Gul Rahman
- Subjects
Photocurrent ,Materials science ,Dopant ,General Chemical Engineering ,Doping ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Hematite ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Dielectric spectroscopy ,X-ray photoelectron spectroscopy ,chemistry ,visual_art ,Electrochemistry ,visual_art.visual_art_medium ,Water splitting ,0210 nano-technology ,Titanium - Abstract
Elemental doping is considered to be an effective strategy to improve the photoelectrochemical (PEC) activity of hematite (α-Fe2O3) as a photoanode for water splitting, but the precise function (s) of the dopant remains unclear. In this study, we report on the structural and charge separation properties of titanium-doped hematite (Ti doped Fe2O3) films prepared by a simple electrospray technique for PEC water oxidation. The effect of Ti doping on the structure, morphology, light absorption, and electrical and photoelectrochemical properties was investigated on α-Fe2O3 films. SEM images revealed a reduction in particle sizes for 2% Ti doped α-Fe2O3, while an increase in particle size was observed for higher Ti content. XRD confirmed the presence of α-Fe2O3 without any impurity or other phases. From XPS spectra, the incorporation of Ti was confirmed in the form of Ti4+ as predominant species while no impurities from the substrate were detected. When the Ti doped Fe2O3 (2% Ti) film was used as a photoanode in a PEC cell, it delivered the best performance with a maximum photocurrent density of 1.09 mA cm−2 (at 1.8 V vs. RHE and under standard 1 sun illumination conditions (AM 1.5 G, 100 mW cm−2)), which is 2 times higher than that of the un-doped α-Fe2O3 (0.51 mA cm−2). The photoelectrode also showed a superior incident photon to current efficiency (IPCE) as compared to an un-doped α-Fe2O3. This enhancement in performance was attributed to the better charge separation and transport properties of α-Fe2O3 due to Ti doping, as revealed by an electrochemical impedance spectroscopy (EIS) analysis.
- Published
- 2019
36. Oxygen vacancy revived phonon-glass electron-crystal in SrTiO3
- Author
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Altaf Ur Rahman, Woo Hyun Nam, Nguyen Van Du, Soonil Lee, Jamil Ur Rahman, Won-Seon Seo, Gul Rahman, Weon Ho Shin, and Myong-Ho Kim
- Subjects
010302 applied physics ,Materials science ,Condensed matter physics ,Phonon scattering ,Phonon ,Annealing (metallurgy) ,chemistry.chemical_element ,02 engineering and technology ,Partial pressure ,Electron ,021001 nanoscience & nanotechnology ,01 natural sciences ,Oxygen ,Thermal conductivity ,chemistry ,Electrical resistivity and conductivity ,0103 physical sciences ,Materials Chemistry ,Ceramics and Composites ,0210 nano-technology - Abstract
Controlling oxygen vacancy in undoped SrTiO3 was used to realize the phonon-glass electron-crystal (PGEC) concept. The undoped SrTiO3 samples were synthesized through solid-state-reaction method in air and then reduced through annealing under low oxygen partial pressure conditions. We show that decreasing the oxygen partial pressure (Po2) results in increase of the electrical conductivity, and the oxygen vacancies act as phonon scattering centers, which lead to decrease in the lattice thermal conductivity. Both the enhanced electrical conductivity (σ) and reduced thermal conductivity (κ) were achieved simultaneously through oxygen vacancy in undoped SrTiO3. This significantly increases the ratio of σ/κ that results in an enormously enhanced ZT value of about 13 times larger as compared with the samples reduced under relatively high Po2. Density-functional theory calculations also reveal that oxygen vacancies in SrTiO3 reduce the band-gap, and consequently increase the electrical conductivity.
- Published
- 2019
37. Nickel Oxide-incorporated Polyaniline/Polyvinyl Alcohol Composite for Enhanced Antibacterial Activity
- Author
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Zahid Hussain Khan, Mansoor Khan, Muhammad Saleem Khan, Anwar-ul-Haq Ali Shah, Gul Rahman, and Luqman Ali Shah
- Subjects
Materials science ,Nickel oxide ,Composite number ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Polyvinyl alcohol ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Polyaniline ,Physical and Theoretical Chemistry ,In situ polymerization ,0210 nano-technology ,Antibacterial activity ,Nuclear chemistry - Abstract
The development of biocompatible, cost effective and more efficient materials to control or inhibit the growth of microorganisms in necessary to fight against resistant microbes. Here, we demonstrate the synthesis of nickel oxide-incorporated polyaniline/polyvinyl alcohol (PANI/PVA/NiOx) composite material by single-step polymerization and its application as antibacterial agent. The composite films were characterized using UV-visible spectroscopy (UV-Vis), Thermogravimetric analysis (TGA), Fourier Transform Infrared spectroscopy (FTIR), X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). UV-Vis spectra revealed the enhancement in absorption properties of PANI/PVA/NiOx with optimum 5% incorporation of NiOx. TGA results indicated slightly enhanced thermal stability of the PANI/PVA/NiOx composite film as compared to PANI/PVA. FTIR spectra for composites revealed the existence of NiOx in polymers. However the crystallinity of PANI/PVA was not much affected. The antibacterial activity of the prepared composites was examined against four different gram negative bacteria, Salmonella, Shigella, Pseudomonas and Escherichia coli (E. coli). The composite exhibited excellent antibacterial activity against E. coli, Salmonella and Shigella while pseudomonas showed some resistance. Based on the results, PANI/PVA/ NiOx (5%) composite showed the highest activity against the tested bacterial strains, thus showing its potential to be used as an effective antibacterial agent.
- Published
- 2019
38. Effect of SnO2 incorporation on the photoelectrochemical properties of α-Fe2O3–SnO2 nanocomposites prepared by hydrothermal method
- Author
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Gul Rahman, Abdur Rahim, Noureen Amir Khan, Anwar ul Haq Ali Shah, Burhan Khan, and Sang Youn Chae
- Subjects
General Materials Science ,Condensed Matter Physics - Published
- 2022
39. Defects-driven magnetism in bulk α-Li3N
- Author
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Gul Rahman and Saima Kanwal
- Subjects
Condensed Matter - Materials Science ,Materials science ,Condensed matter physics ,Magnetic moment ,Magnetism ,Fermi energy ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Condensed Matter::Materials Science ,Ferromagnetism ,Vacancy defect ,0103 physical sciences ,Atom ,Physics::Atomic and Molecular Clusters ,Antiferromagnetism ,Condensed Matter::Strongly Correlated Electrons ,Density functional theory ,010306 general physics ,0210 nano-technology - Abstract
\textit{Ab-initio} calculations based on density functional theory with local spin density approximation are used to study defects-driven magnetism in bulk $\alpha$-Li$ _{3}$N. Our calculations show that bulk Li$ _{3} $N is a non-magnetic semiconductor. Two types of Li vacancies (Li-I and Li-II) are considered, and Li-vacancies (either Li-I or Li-II type) can induce magnetism in Li$ _{3}$N with a total magnetic moment of 1.0 $\mu_{\rm B}$ which arises mainly due to partially occupied N-$p$-orbitals around the Li vacancies. The defect formation energies dictate that Li-II vacancy, which is in the Li$ _{2}$N plane, is thermodynamically more stable as compared with Li-I vacancy. The electronic structures of Li-vacancies show half-metallic behavior. On the other hand N-vacancy does not induce magnetism and has a larger formation energy than Li-vacancies. N vacancy derived bands at the Fermi energy are mainly contributed by the Li atoms. Carbon is also doped at Li-I and Li-II sites, and it is expected that doping C at Li-I site is thermodynamically more stable as compared with Li-II site. Carbon can induce metallicity with zero magnetic moment when doped at Li-I site, whereas magnetism is observed when Li-II site is occupied by the C impurity atom and C-driven magnetism is spread over the N atoms as well. Carbon can also induce half-metallic magnetism when doped at N site in Li$ _{3}$N, and has a smaller defect formation energy as compared with Li-II site doping. The ferromagnetic (FM) and antiferromagnetic (AFM) coupling between the C atoms is also investigated, and we conclude that FM state is more stable than the AFM state., Comment: Accepted; J. Mag. Mag. Mat. (2018)
- Published
- 2018
40. Flexible bacterial cellulose-based BC-SiO2-TiO2-Ag membranes with self-cleaning, photocatalytic, antibacterial and UV-shielding properties as a potential multifunctional material for combating infections and environmental applications
- Author
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Quyet Van Le, Kifayat U. Rahman, Andreia Sofia Monteiro, Gul Rahman, Ghaws U. Rahman, Elias Paiva Ferreira-Neto, Sajjad Ullah, Rashida Parveen, Rafael R. Domeneguetti, Sidney José Lima Ribeiro, University of Peshawar, Universidade Estadual Paulista (Unesp), Government Girls Degree College, Duy Tan University, and Federal University of Mato Grosso do Sul
- Subjects
Materials science ,Silver ,Absorption spectroscopy ,02 engineering and technology ,010501 environmental sciences ,engineering.material ,01 natural sciences ,Bacterial cellulose ,chemistry.chemical_compound ,Coating ,TiO2 ,Chemical Engineering (miscellaneous) ,Crystal violet ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Process Chemistry and Technology ,021001 nanoscience & nanotechnology ,Pollution ,Tetraethyl orthosilicate ,Antibacterial ,Membrane ,chemistry ,Chemical engineering ,Photocatalysis ,engineering ,0210 nano-technology ,Antibacterial activity ,Photoactivity ,Self-cleaning - Abstract
Made available in DSpace on 2021-06-25T11:08:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01 This research study reports the formation of flexible and multifunctional organic-inorganic hybrid membranes (BC-SiO2-TiO2/Ag) based on bacterial cellulose (BC) that contain photoactive (TiO2) and antibacterial (Ag) components, rendering them photocatalytic, self-cleaning and UV-shielding properties (due to TiO2) as well as antibacterial activity. Coating of BC with sol-gel derived silica and titania particles was achieved through hydrolysis-polycondensation of tetraethyl orthosilicate and titanium (IV) isopropoxide, respectively, and a soft hydrothermal treatment (140 °C, 20 h) was used to obtain well-crystalline TiO2. The prepared BC-SiO2-TiO2/Ag photoactive membranes were characterized by an array of analytical techniques including XRD, XRF, SEM-EDS, electronic absorption spectroscopy and vibrational spectroscopy. The morphology of TiO2 coatings changes from a homogenous film-like smooth one to a rougher one consisting of randomly oriented titania particles (170 ± 35 nm) upon increasing the TiO2 loading of the membranes. These prepared photoactive BC-SiO2-TiO2 membranes exhibited excellent TiO2-loading dependent photocatalytic/self-cleaning activity towards crystal violet dye deposited as an over-layer on the surface of the membranes, degrading 97 % of the dye within 50 min of UV illumination. In addition to good photoactivity, the BC-SiO2-TiO2/Ag membranes demonstrated reasonable antibacterial activity against five different bacterial strains under dark conditions. These flexible BC-based hybrid membranes with photocatalytic, self-cleaning, antibacterial properties have the potential to be used in the design of self-cleaning and antibacterial surfaces, filters and facemasks that could be easily disinfected under UV irradiation from a lamp or natural sunlight and safely discarded and even recycled. Institute of Chemical Sciences University of Peshawar Institute of Chemistry São Paulo State University - UNESP, CP 355 Government Girls Degree College Institute of Research and Development Duy Tan University Institute of Physics Federal University of Mato Grosso do Sul Institute of Chemistry São Paulo State University - UNESP, CP 355
- Published
- 2021
- Full Text
- View/download PDF
41. RELATIVE COMPARISON OF STABILITY AND DEGRADATION OF METHYLCOBALAMIN TABLETS OF DIFFERENT BRANDS AT DIFFERENT STORAGE SETTINGS
- Author
-
RAZIQ, ABDUL, primary, JAN, SYED UMER, additional, GUL, RAHMAN, additional, KHAN, YOUSAF, additional, AMAN, TAJALA, additional, and SHAH, PERVAIZ AKHTAR, additional
- Published
- 2021
- Full Text
- View/download PDF
42. Steel Structures Usage and Steel Production: A Case Study in Afghanistan
- Author
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Gul Rahman Abdulrahimzai, Haroon Rasheed Safi, and Asil Ahmad Halimyar
- Published
- 2020
43. Optimizing Intersection Performance Using Sidra Program on Baraki Intersection Kabul Afghanistan
- Author
-
Ahmad Walid Yusufi, Khawaja Abdul Rahman Sediqi, Haroonrasheed Safi, Suhrab Aryan, Gul Rahman Abdulrahimzai, and Rustam Hafizyar
- Subjects
Transport engineering ,Traffic congestion ,Level of service ,Computer science ,Urbanization ,Fuel efficiency ,Population growth ,Production (economics) ,Queue ,Intersection (aeronautics) - Abstract
congestion in road networks and intersections is a ubiquitous problem which occurs due to several causes. Kabul city the capital of Afghanistan has felt this propagating problem from the establishment of its new administration in 2001. The rapid population growth urbanization, low capacity of roads, and lack of a comprehensive strategy to manage traffic systems and tackle traffic congestions are the leading contributors to the traffic congestion problem. Therefore, it is vital to utilize advanced software tools to explore possible solutions to the traffic congestion problem. This study was aimed to evaluate and analyze Baraki Intersection in Kabul city Afghanistan using SIDRA INTERSECTION 5 software. It assessed traffic performance in one of the most important junctions in Kabul based on parameters such as Level of service, delays, Queue, Fuel consumption and production of CO2, CO, (CH2O)n, NO x. The results showed that there was a notable time delay, dangerous amount of emissions and low level of service (LOS F). After a comprehensive investigation of the results it was concluded that building an underpass from north to south direction will significantly reduce delays and emissions and increase the level of service until 2030.
- Published
- 2020
44. Tuning the optoelectronic properties of hematite with rhodium doping for photoelectrochemical water splitting using density functional theory approach
- Author
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Gul Rahman, Muhammad Adil, Abdur Rauf, Wei Qun, Ejaz Ahmed, Shabeer Ahmad Mian, and Zia Mohy Ud Din
- Subjects
Renewable energy ,Materials science ,Band gap ,Science ,Energy science and technology ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Article ,Absorption (electromagnetic radiation) ,Photocurrent ,Multidisciplinary ,business.industry ,Photoconductivity ,Physics ,Doping ,Hematite ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,visual_art ,visual_art.visual_art_medium ,Medicine ,Optoelectronics ,Water splitting ,Other photonics ,Density functional theory ,0210 nano-technology ,business - Abstract
Hematite (Fe2O3) is one of the best candidates for photoelectrochemical water splitting due to its abundance and suitable bandgap. However, its efficiency is mostly impeded due to the intrinsically low conductivity and poor light absorption. In this study, we targeted this intrinsic behavior to investigate the thermodynamic stability, photoconductivity and optical properties of rhodium doped hematite using density functional theory. The calculated formation energy of pristine and rhodium doped hematite was − 4.47 eV and − 5.34 eV respectively, suggesting that the doped material is thermodynamically more stable. The DFT results established that the bandgap of doped hematite narrowed down to the lower edge (1.61 eV) in the visible region which enhanced the optical absorption and photoconductivity of the material. Moreover, doped hematite has the ability to absorb a broad spectrum (250–800) nm. The enhanced optical absorption boosted the photocurrent and incident photon to current efficiency. The calculated results also showed that the incorporation of rhodium in hematite induced a redshift in optical properties.
- Published
- 2020
45. Reduced Graphene Oxide/Poly(Pyrrole-co-Thiophene) Hybrid Composite Materials: Synthesis, Characterization, and Supercapacitive Properties
- Author
-
Salma Bilal, Gul Rahman, Sami Ullah, Humaira Seema, and Anwar ul Haq Ali Shah
- Subjects
Supercapacitor ,Horizontal scan rate ,Materials science ,Polymers and Plastics ,Scanning electron microscope ,Graphene ,power density ,General Chemistry ,Dielectric spectroscopy ,law.invention ,reduced graphene oxide (RGO) ,lcsh:QD241-441 ,poly(pyrrole-co-thiophene) (COP) ,lcsh:Organic chemistry ,law ,supercapacitor ,Composite material ,Cyclic voltammetry ,Fourier transform infrared spectroscopy ,Hybrid material ,energy density - Abstract
Reduced graphene oxide/poly(pyrrol-co-thiophene) (RGO/COP), prepared by facile in-situ oxidative copolymerization, is reported as a new hybrid composite material with improved supercapacitance performance as compared to the respective homopolymers and their composites with RGO. The as-prepared hybrid materials were characterized with ultraviolet&ndash, visible (UV&ndash, Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis. The electrochemical behavior and energy storage properties of the materials were tested by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrostatic impedance spectroscopy (EIS) techniques in 0.5 M H2SO4. The specific capacitance (Csp) for RGO/COP calculated from the CV curve was 467 F/g at a scan rate of 10 mV/s. While the Csp calculated from the GCD was 417 F/g at a current density of 0.81 A/g. The energy density calculated was 86.4 Wh/kg with a power density of 630 W/kg. The hybrid composite exhibits good cyclic stability with 65% capacitance retention after 1000 cycles at a scan rate of 100 mV/s. The present work brings a significance development of RGO/COP composites to the electrode materials for pseudocapacitive application.
- Published
- 2020
46. Reduced Graphene Oxide/Poly(Pyrrole
- Author
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Anwar Ul Haq Ali, Shah, Sami, Ullah, Salma, Bilal, Gul, Rahman, and Humaira, Seema
- Subjects
reduced graphene oxide (RGO) ,power density ,supercapacitor ,poly(pyrrole-co-thiophene) (COP) ,energy density ,Article - Abstract
Reduced graphene oxide/poly(pyrrol-co-thiophene) (RGO/COP), prepared by facile in-situ oxidative copolymerization, is reported as a new hybrid composite material with improved supercapacitance performance as compared to the respective homopolymers and their composites with RGO. The as-prepared hybrid materials were characterized with ultraviolet–visible (UV–Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis. The electrochemical behavior and energy storage properties of the materials were tested by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrostatic impedance spectroscopy (EIS) techniques in 0.5 M H2SO4. The specific capacitance (Csp) for RGO/COP calculated from the CV curve was 467 F/g at a scan rate of 10 mV/s. While the Csp calculated from the GCD was 417 F/g at a current density of 0.81 A/g. The energy density calculated was 86.4 Wh/kg with a power density of 630 W/kg. The hybrid composite exhibits good cyclic stability with 65% capacitance retention after 1000 cycles at a scan rate of 100 mV/s. The present work brings a significance development of RGO/COP composites to the electrode materials for pseudocapacitive application.
- Published
- 2020
47. Structural and electronic properties of two-dimensional hydrogenated Xenes
- Author
-
Gul Rahman and Asad Mahmood
- Subjects
Materials science ,Condensed matter physics ,Magnetic moment ,Graphene ,Band gap ,Fermi level ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Coupling (probability) ,01 natural sciences ,law.invention ,symbols.namesake ,law ,0103 physical sciences ,symbols ,Stanene ,General Materials Science ,Density functional theory ,010306 general physics ,0210 nano-technology ,Electronic band structure - Abstract
Structural and electronic properties of pristine two-dimensional group IV Xenes (X=C, Si, Ge, Sn, Pb) and hydrogenated Xenes are studied, using density functional theory (DFT) calculations with and without spin-orbit coupling (SOC). The pristine hexagonal monolayer Xenes show buckled structure upon relaxation except graphene. The buckling $\delta$ increases linearly from graphene to plumbene. The bond angle $\theta$ between the X atoms is correlated with the degree of hybridization.% $D The band structures without SOC of group-IV Xenes are semi-metallic. However, inclusion of SOC mainly opens the bandgap at the Dirac point. The degree of hybridization and bandgap opening due to SOC are mainly explained in terms of the contribution of $p_{\mathrm{x}}/p_{\mathrm{y}}$ and $p_{z}$ electronic states at Fermi level. Semi hydrogenation (SH) leads to enhanced buckling in all Xenes which indicate a tendency towards more $sp^3$ like structures. The electronic structures of SH Xenes do not show Dirac cones. Incorporating SOC in the non-spin polarized band structure calculations results into splitting of the states. On the other hand, spin polarized band structures show magnetism with magnetic moment of 1.0~$\mu_{\rm{B}}$ and all SH Xenes are magnetic semiconductor except SH plumbene. Full hydrogenation vanishes buckling upon relaxation and the structure becomes planar implying $sp^2$-like hybridization. The band structures for FH Xenes turns out to be semiconducting and the Dirac cones also disappear. The bandgap changes from indirect to direct at FH stanene, while FH plumbene turns out to be semi-metallic. No spin polarized states are observed. The effect of SOC does not instigate any noteworthy changes in the bandgap for FH graphene to FH stanene. On the other hand, the SOC gives rise to bandgap of 0.47 eV in FH plumbene, which is otherwise a semi-metal.
- Published
- 2020
48. Ternary composites of polyaniline with polyvinyl alcohol and Cu by inverse emulsion polymerization: A comparative study
- Author
-
Khurshid Ali, Salma Bilal, Anwar-ul-Haq Ali Shah, Gul Rahman, and Rizwan Ullah
- Subjects
Materials science ,Polymers and Plastics ,General Chemical Engineering ,Organic Chemistry ,Emulsion polymerization ,Inverse ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Polyvinyl alcohol ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Polyaniline ,Composite material ,0210 nano-technology ,Ternary operation - Published
- 2018
49. A Review on Biological Process for Improvement of Soil Properties in Geotechnical Engineering
- Author
-
Rustam Hafizyar and Gul Rahman Abdulrahimzai
- Published
- 2019
50. Efficient hydrogen evolution performance of phase-pure NiS electrocatalysts grown on fluorine-doped tin oxide-coated glass by facile chemical bath deposition
- Author
-
Sang Youn Chae, Gul Rahman, and Oh-Shim Joo
- Subjects
chemistry.chemical_classification ,Tafel equation ,Materials science ,Nickel sulfide ,Sulfide ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,02 engineering and technology ,Overpotential ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electrocatalyst ,Tin oxide ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Fuel Technology ,Chemical engineering ,chemistry ,0210 nano-technology ,Chemical bath deposition - Abstract
The production of hydrogen, the future fuel, on stable, efficient, and robust electrocatalysts represents an attractive approach for the conversion and storage of carbon-free energy resources. In this study, earth-abundant nickel sulfide (NiS) electrocatalyst were grown on fluorine-doped tin oxide (FTO) substrate by a simple and cost-effective chemical bath deposition for hydrogen evolution reaction (HER). Energy dispersive X-ray analysis and X-ray photoelectron spectra indicated the presence of highly pure NiS. The HER performance of the catalyst was examined in alkaline solution (1.0 M NaOH; pH = 13.5). Notably, NiS film prepared at 100 °C demonstrated superior HER activity with an overpotential of 290 mV to afford a current density of 10 mA/cm2 and a Tafel slope of 143.4 mV/dec which are among the promising results obtained for sulfide-based HER electrocatalysts. The catalyst exhibited 100% faradaic efficiency and electrochemical stability which indicate its potential as noble-metal-free HER electrocatalyst.
- Published
- 2018
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