1,338 results on '"Ahmad, Umar"'
Search Results
152. Correction to: Environmental efficiency and the role of energy innovation in emissions reduction
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Anser, Muhammad Khalid, Iqbal, Wasim, Ahmad, Umar Suffian, Fatima, Arooj, and Chaudhry, Imran Sharif
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- 2020
- Full Text
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153. Heterogeneous effect of oil production on environmental degradation: panel evidence from OPEC member countries
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Ahmad Umar Ali, Ismail Aliyu Danmaraya, Aminu Hassan Jakada, Bello Alhaji Ibrahim, and Suraya Mahmood
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Distributed lag ,Macroeconomics ,Short run ,business.industry ,Strategy and Management ,Renewable energy ,General Energy ,Negative relationship ,Greenhouse gas ,Economics ,Energy source ,business ,Environmental degradation ,Constraint (mathematics) - Abstract
Purpose The purpose of this paper is to look at the asymmetric effect of oil production on environmental degradation in OPEC member countries from 1970–2019. Design/methodology/approach The authors build a nonlinear panel ARDL–PMG model using the Shin et al. (2014) nonlinear autoregressive distributed lag (ARDL) approach in panel form to assess both the short- and long-run impact of positive and negative oil production movements on CO2 emissions. Findings The result demonstrates that the variables are cointegrated. According to the linear long run coefficients, oil production, FDI inflows and economic growth both have a positive and significant relationship with CO2 emissions, implying that they deteriorate environmental quality in OPEC countries, while renewable energy has a negative relationship with CO2, implying that increasing renewable energy improves environmental quality. The asymmetric findings prove that positive and negative shocks of oil production exert a positive effect on carbon emissions in short run and long run. Research limitations/implications To begin with, the empirical assessments do not include all OPEC member nations; researchers are advised to resolve this constraint by looking at the economies of other OPEC members. Albeit the lack of data for other energy sources may serve as another constraint of this research, future research is expected to broaden the current framework via other energy sources such as nuclear, electricity, biomass, solar as well as wind. Originality/value The research adds to the body of knowledge as many of the prevailing studies in the literature failed to look at the asymmetric effect of oil production on the quality of environment. This is another gap in the literature that the current study is set out to fill. This study adds oil production as an explanatory variable and helps to extend the existing literature for OPEC countries, which could propose a solution to deal with ensuing environmental issues.
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- 2021
154. Effect of Active Learning Technique on Self-Concept and Academic Achievement Among Juniour Secondary School Students in Geometry in Bosso, Niger State, Nigeria
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null Aliyu Alhaji ZAKARIYYA, null Ahmad Umar MANKO, null Kure D. ISAH, and null Ochidali Apollos ADUOJO
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This study investigated the effect of active learning technique on self-concept and academic achievement in geometry among junior secondary school students in Bosso local government, Niger State, Nigeria. The study adopted a pre-test, post-test quasi-experimental design. The study used 135 students in junior secondary school III (JSS III). The experimental group consisted of 67 while control group consisted of 68 students. The researcher adopted and validated two instruments. These include: students self-concept toward geometry (SSTG), likert-type scales with reliability coefficient of 0.5, geometry Achievement test (GAT), and five items theory question with reliability coefficient of 0.5. The experimental period lasted for four weeks during which the control group was taught using discussion method while the experimental group was taught using active learning technique. Four research questions were answered and their corresponding four research hypotheses were tested. The research questions were answered using mean and standard deviation. Hypothesis testing was done using inferential statistic of t-test for equality of means of independent sample, Mann-Whitney U test at p≤0.05, level of significance. There was a significance difference between the post-test mean scores of experimental and control group in favour of the experimental group. There was no significance difference in self-concepts of the subjects in the experimental group. It is recommended that active learning technique should be used in teaching mathematics.
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- 2021
155. Manipulating the Electrocatalytic Performance of NiCoP Nanowires by V Doping Under Acidic and Basic Conditions for Hydrogen and Oxygen Evolution Reactions
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Xiaojie Tan, Yuchen Sun, Zhongxin Duan, Ahmad Umar, Wei-chao Zhang, and Xiang Wu
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chemistry.chemical_compound ,Materials science ,Chemical engineering ,Hydrogen ,chemistry ,Doping ,Oxygen evolution ,Nanowire ,chemistry.chemical_element ,General Materials Science ,Bifunctional ,Hydrogen production - Abstract
It is critical to design bifunctional nonprecious electrocatalysts with low costs and high efficiency for hydrogen production. Conventional electrocatalysts, on the other hand, frequently exhibit s...
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- 2021
156. Enhanced photoresponsivity of anatase titanium dioxide (TiO2)/nitrogen-doped graphene quantum dots (N-GQDs) heterojunction-based photodetector
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Hassan Algadi, Mohd. Shkir, Ahmad Umar, and Hasan Albargi
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Anatase ,Materials science ,Polymers and Plastics ,Graphene ,business.industry ,Materials Science (miscellaneous) ,Photodetector ,chemistry.chemical_element ,Heterojunction ,law.invention ,chemistry ,law ,Quantum dot ,Materials Chemistry ,Ceramics and Composites ,Optoelectronics ,Thin film ,business ,High-resolution transmission electron microscopy ,Titanium - Abstract
Low-cost and high-performance UV photodetector (PD) based on anatase titanium dioxide (TiO2) and nitrogen-doped graphene quantum dots (N-GQDs) bilayer heterojunction were fabricated on a commercial SiO2/Si substrate by drop-casting the N-GQDs solution on the surface of anatase TiO2 thin film, which was initially prepared by thermally oxidizing a DC-sputtered titanium (Ti) film in air. The anatase TiO2 and N-GQDs films were characterized with several techniques in order to study their structure and morphology properties. XRD, XPS, and AFM revealed that the phase of the as-sputtered Ti film transformed to a highly crystalline pure anatase TiO2 film when thermally oxidized at 600 °C in air. In addition, TEM, HRTEM, and FTIR revealed that the N-GQDs are highly crystalline and narrowly distributed in size. Furthermore, the optical and UV light harvesting properties of photodetectors based on pure anatase TiO2 film (without N-GQDs) and anatase TiO2 (with N-GQDs) were investigated. The photoresponsivity of the hybrid photodetector based on anatase TiO2/N-GQDs heterojunction has been enhanced by almost 2.5 times in magnitude than that of the photodetector based on pure anatase TiO2 film. This result was validated by elucidated energy band alignment between the anatase TiO2 and N-GQDs films, which resulted in a higher absorption rate, and an efficient transport mechanism in the hybrid junction-based photodetector than that of the pure TiO2-based photodetector.
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- 2021
157. Investigation of the Photoluminescence and Nonlinear Optical Properties of Ce2O3–TiO2 Nanocomposites
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K. Mani Rahulan, R. Seema, G. Vinitha, Ahmad Umar, P. C. Karthika, Manickam Sasidharan, and S. Vivekananthan
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Nanocomposite ,Photoluminescence ,Materials science ,Biomedical Engineering ,Analytical chemistry ,chemistry.chemical_element ,Bioengineering ,Saturable absorption ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Laser ,01 natural sciences ,0104 chemical sciences ,law.invention ,Cerium ,Wavelength ,chemistry ,Absorption edge ,law ,Continuous wave ,General Materials Science ,0210 nano-technology - Abstract
This paper reports the photoluminescence and nonlinear optical (NLO) properties of Ce2O3–TiO2 nanocomposites synthesized via sol–gel process with different concentrations of cerium. The physical characterization studies by means of XRD indicated for the successful incorporation of Ce into the lattice of TiO2, while the UV-visible spectra for an absorption edge shift of TiO2 to the higher wavelength side following the Ce addition, and FESEM analysis for the morphology and particles sizes of the synthesized materials. On testing of the photoluminescence properties recorded through time-resolved fluorescence (TCSPC) technique, a decrease in the intensity of TiO2 with that of increased Ce concentration was observed and is due to an escalation in the number of oxygen vacancies. Further, the observation NLO properties for Ce2O3–TiO2 was done by a Z-scan technique of 5ns continuous wave (cw) laser at 532 nm, where the involvement of active mechanisms in the nonlinear refraction and nonlinear absorption are due to the saturable absorption (SA) and nonlinear thermal effects.
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- 2021
158. Prospects and Challenges of Hydrogen Energy Storage (HES) Application: A Review
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Noor Hasliza Abdul Rahman, Nur Iqtiyani Ilham, Aizat Shazni Ahmad Umar, and Shahril Irwan Sulaiman
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Materials science ,Waste management ,Hydrogen fuel ,General Medicine - Published
- 2021
159. MnO2 Nanoparticles Anchored Multi Walled Carbon Nanotubes as Potential Anode Materials for Lithium Ion Batteries
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Ahmad Umar, Ayeda Y A Mohammed, Faheem Ahmed, Hatem Abuhimd, Hasan Albargi, Ahmed Ibrahim, Mohsen Ali M. Alhmami, Tubia Almas, Hassan Algadi, and Luis Castañeda
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Battery (electricity) ,Materials science ,Biomedical Engineering ,Nanoparticle ,chemistry.chemical_element ,Bioengineering ,02 engineering and technology ,General Chemistry ,Carbon nanotube ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,law.invention ,Anode ,chemistry ,Chemical engineering ,law ,Hydrothermal synthesis ,General Materials Science ,Lithium ,0210 nano-technology ,Current density ,Faraday efficiency - Abstract
Herein, we report a facile hydrothermal synthesis of MnO2 nanoparticles anchored multi walled carbon nanotubes (MnO2@MWCNTs) as potential anode materials for lithium-ion (Li-ion) batteries. The prepared MnO2@MWCNTs were characterized by several techniques which confirmed the formation of MnO2 nanoparticles anchored MWCNTs. The X-ray diffraction and Raman-scattering analyses of the prepared material further revealed the effective synthesis of MnO2@MWCNTs. The fabricated Li-ion battery based on MnO2@MWCNTs exhibited a reversible capacity of ~823 mAhg−1 at a current density of 100 mAg−1 for the first cycle, and delivered a capacity of ~421 mAhg−1 for the 60 cycles. The coulombic efficiency was found to be ~100% which showed excellent reversible charge–discharge behavior. The outstanding performance of the MnO2@MWCNTs anode for the Li-ion battery can be attributed to the distinctive morphology of the MnO2 nanoparticles anchored MWCNTs that facilitated the fast transport of lithium ions and electrons and accommodated a broad volume change during the cycles of charge/discharge.
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- 2021
160. Prevalence of Microorganisms in Acute Pharyngitis from Throat Swab in a tertiary care hospital
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Mahnoor Fatima, Naveed Arshad, Nighat Arif, Mirza Nasheed Baig, Ayesha Jawad, and Mumtaz Ahmad Umar
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medicine.medical_specialty ,business.industry ,Emergency medicine ,medicine ,Tertiary care hospital ,business ,Acute Pharyngitis ,Throat swab - Abstract
Background: Acute pharyngitis is the inflammation of the mucous membrane of oropharynx which is caused by various infectious organisms like bacteria, viruses and fungi. The other less common seen causes include allergies and gastro-esophageal reflux disease. Aim: To look for range of microorganisms involved in causing acute pharyngitis on throat swab specimens. Methods: After getting consent all the pharyngitis patients attending ENT Department at Akbar Niazi Teaching Hospital (ANTH), Islamabad from January to June 2017 were included in the study. From total of 100 patients throat swabs were obtained by established aseptic method and were sent for culture. The organisms involved were recognized by biochemical tests & their propensity to antimicrobial agents was established by established methods. Data was entered and analyzed by using SPSS v.21. Results: Out of 100 specimens’ microorganisms were identified in 25 specimens while 75 specimens had no growth. Streptococcus pyogenes was the frequently seen organism 9(90%), while the list was followed by Staphylococcus aureus 14(56%) and Candida albicans 3(12%). In 40% single pathogen was identified with Streptococcus pyogenes in 9 samples (90%) and Staphylococcus aureus in 1(10%), whereas 60% of the culture reports were that of the mix infection. Conclusion: The study concluded that streptococcus pyogenes and staphylococcus aureus were responsible for majority of single organism infections, while candida albicans together with these bacteria were isolated from mixed infections. Keywords: Pharyngitis; Streptococcus pyogenes; Throat; Microorganisms.
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- 2021
161. Co-Doped ZnO Nano-Agglomerates as a Potential Scaffold for Non-Enzymatic Hydrogen Peroxide Sensing
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Ahmad Umar, Ramesh Kumar, Rajesh Kumar, Ahmed A. Ibrahim, Mohsen A. M. Alhamami, Hassan Algadi, Suvarcha Chauhan, and M. S. Chauhan
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General Materials Science - Abstract
Co-doped ZnO nano-agglomerates were synthesized by a facile solution process. Several characterization techniques revealed the successful doping of the ZnO by Co ions. FESEM results showed the agglomeration of the Co-doped ZnO nanoparticles to form large-sized nano-agglomerates. The diameters of the spherical nanoparticles and the agglomerates were not found to be uniform. The diameters of the nano-agglomerates ranged from ~25 nm–120 nm. XRD spectrum confirmed the Wurtzite hexagonal phase of ZnO in Co-doped ZnO nanoagglomerates. The average particle size for Co-doped ZnO nano-agglomerates was 20.68 nm. The sensing parameters were examined by using Co-doped ZnO nano-agglomerates modified gold electrode through cyclic voltammetric and amperometric analysis. The sensitivity of 70.73 μAmM−1cm−2 and very low-detection limit of 0.2 μM was observed for H2O2. The corresponding linear dynamic concentration range was 0.2–1633 μM. The excellent sensing activities of the Co-doped ZnO nano-agglomerates for H2O2 were attributed to the improved intrinsic electric properties and increased inner defects density, particularly near the interface region.
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- 2021
162. Enhanced NO2 gas sensor device based on supramolecularly assembled polyaniline/silver oxide/graphene oxide composites
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Mabkhoot A. Alsairi, Sheikh A. Akbar, Yao Wang, Ahmad Umar, Hassan Algadi, Ahmed Ibrahim, and Hasan Albargi
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010302 applied physics ,Materials science ,Graphene ,Process Chemistry and Technology ,Composite number ,Oxide ,Nanoparticle ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,0103 physical sciences ,Polyaniline ,Materials Chemistry ,Ceramics and Composites ,Crystallite ,Fourier transform infrared spectroscopy ,Composite material ,0210 nano-technology ,Silver oxide - Abstract
Herein, we report a successful synthesis of supramolecularly assembled polyaniline/silver oxide/graphene oxide composite (PANI/Ag2O/GO) for enhanced NO2 gas sensing application. The PANI/Ag2O/GO composite was synthesized by facile stirring followed by an ultrasonication process. The prepared material was characterized by different techniques such as x-ray diffraction, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and Raman-scattering spectroscopy. The detailed analysis revealed that the average crystallite sizes of PANI/Ag2O and PANI/Ag2O/GO composites were found to be 37.37 nm and 41.55 nm, respectively. FESEM and TEM analysis showed coral-like rough-surfaced and extensively agglomerated morphology for PANI and ultrathin flexible sheet-like morphology for GO. Ag2O nanoparticles with diameters 20–30 nm were well incorporated in the GO sheets and PANI matrix in the case of PANI/Ag2O/GO composites. The synthesized materials were used to make resistive sensor devices that had a high response to NO2 gas. The fabricated sensors were examined at various temperatures to obtain the optimal sensing temperature. The fabricated NO2 gas sensor device based on PANI/Ag2O/GO composite exhibited a highest sensitivity of 5.85 for 25 ppm at an optimized temperature (100 °C) as compared to the pure PANI (2.5) and PANI/Ag2O composite (3.25). Further, the fabricated sensor device based on PANI/Ag2O/GO composite was also examined at different NO2 gas concentrations.
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- 2021
163. Reproducibility in Cancer Transcriptomics Research
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Ahmad Umar
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Open Science ,Computational Cancer Research ,Reproducibility - Abstract
Slide deck of my talk on Reproducibility in Cancer Transcriptomics ResearchduringOctober Omics Codeathonorganised by theAfrican Society for Bioinformatics and Computational Biology.  
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- 2022
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164. The Biology of Phylogenetic
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Ahmad Umar
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Phylogenetic, Phylogeny, Phylogenome, Software - Abstract
Slide deck of my talk about the biology of phylogenetic.Phylogenies represent evolutionary relationships and observe how relatedness aregenes, genomes and species. I also talked about the application of phylogenetic in forensic investigation, in bioinformatics and computing, in identifying pathogen for surveillance and in classification.  
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- 2022
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165. 2D Nanomaterial-Based Surface Plasmon Resonance Sensors for Biosensing Applications
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Sachin Singh, Pravin Kumar Singh, Ahmad Umar, Pooja Lohia, Hasan Albargi, L. Castañeda, and D. K. Dwivedi
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2D nanomaterials ,surface plasmon resonance sensor ,dichalcogenides ,biosensing ,Mechanical engineering and machinery ,TJ1-1570 - Abstract
The absorption and binding energy of material plays an important role with a large surface area and conductivity for the development of any sensing device. The newly grown 2D nanomaterials like black phosphorus transition metal dichalcogenides (TMDCs) or graphene have excellent properties for sensing devices’ fabrication. This paper summarizes the progress in the area of the 2D nanomaterial-based surface plasmon resonance (SPR) sensor during last decade. The paper also focuses on the structure of Kretschmann configuration, the sensing principle of SPR, its characteristic parameters, application in various fields, and some important recent works related to SPR sensors have also been discussed, based on the present and future scope of this field. The present paper provides a platform for researchers to work in the field of 2D nanomaterial-based SPR sensors.
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- 2020
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166. Surface Modification of Bentonite with Polymer Brushes and Its Application as an Efficient Adsorbent for the Removal of Hazardous Dye Orange I
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Wenjuan Guo, Ahmad Umar, Yankai Du, Luyan Wang, and Meishan Pei
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PDMAEMA ,polymer brushes ,Orange I ,dyes removal ,water treatment ,Chemistry ,QD1-999 - Abstract
Poly(2-(dimethylamino)ethyl methacrylate)-grafted bentonite, marked as Bent-PDMAEMA, was designed and prepared by a surface-initiated atom transfer radical polymerization method for the first time in this study. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA) were applied to characterize the structure of Bent-PDMAEMA, which resulted in the successful synthesis of Bent-PDMAEMA. As a cationic adsorbent, the designed Bent-PDMAEMA was used to remove dye Orange I from wastewater. The adsorption property of Bent-PDMAEMA for Orange I dye was investigated under different experimental conditions, such as solution pH, initial dye concentration, contact time and temperature. Under the optimum conditions, the adsorption amount of Bent-PDMAEMA for Orange I dye could reach 700 mg·g−1, indicating the potential application of Bent-PDMAEMA for anionic dyes in the treatment of wastewater. Moreover, the experimental data fitted well with the Langmuir model. The adsorption process obeyed pseudo-second-order kinetic process mechanism.
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- 2020
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167. Bi2WO6/C-Dots/TiO2: A Novel Z-Scheme Photocatalyst for the Degradation of Fluoroquinolone Levofloxacin from Aqueous Medium
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Shelja Sharma, Alex O. Ibhadon, M. Grazia Francesconi, Surinder Kumar Mehta, Sasikumar Elumalai, Sushil Kumar Kansal, Ahmad Umar, and Sotirios Baskoutas
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Bi2WO6/C-dots/TiO2 ,Z-scheme ,photocatalysis ,levofloxacin ,solar irradiation ,Chemistry ,QD1-999 - Abstract
Photocatalytic materials and semiconductors of appropriate structural and morphological architectures as well as energy band gaps are materials needed for mitigating current environmental problems, as these materials have the ability to exploit the full spectrum of solar light in several applications. Thus, constructing a Z-scheme heterojunction is an ideal approach to overcoming the limitations of a single component or traditional heterogeneous catalysts for the competent removal of organic chemicals present in wastewater, to mention just one of the areas of application. A Z-scheme catalyst possesses many attributes, including enhanced light-harvesting capacity, strong redox ability and different oxidation and reduction positions. In the present work, a novel ternary Z-scheme photocatalyst, i.e., Bi2WO6/C-dots/TiO2, has been prepared by a facile chemical wet technique. The prepared solar light-driven Z-scheme composite was characterized by many analytical and spectroscopic practices, including powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), N2 adsorption–desorption isotherm, Fourier-transform infrared spectroscopy (FT-IR), photoluminescence (PL) and UV-vis diffuse reflectance spectroscopy (DRS). The photocatalytic activity of the Bi2WO6/C-dots/TiO2 composite was evaluated by studying the degradation of fluoroquinolone drug, levofloxacin under solar light irradiation. Almost complete (99%) decomposition of the levofloxacin drug was observed in 90 min of sunlight irradiation. The effect of catalyst loading, initial substrate concentration and pH of the reaction was also optimized. The photocatalytic activity of the prepared catalyst was also compared with that of bare Bi2WO6, TiO2 and TiO2/C-dots under optimized conditions. Scavenger radical trap studies and terephthalic acid (TPA) fluorescence technique were done to understand the role of the photo-induced active radical ions that witnessed the decomposition of levofloxacin. Based on these studies, the plausible degradation trail of levofloxacin was proposed and was further supported by LC-MS analysis.
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- 2020
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168. Flexible Laryngoscopy Audit in Outpatient Department of a tertiary care hospital, Islamabad
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Mumtaz Ahmad Umar, Mohibullah Mushwani, and Naveed Arshad
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Background: Flexible laryngoscopy is less operator/patient dependent diagnostic procedure with magnified field and well tolerated diagnostic procedure. Flexible laryngoscopy is tolerable diagnostic procedure with clear and magnified visualization of interior larynx. Aim: To audit the flexible laryngoscope in outpatient department in our local setting. Methods: A retrospective audit survey was carried out in Outpatient ENT Department of Akbar Niazi Teaching Hospital, Islamabad between June 2021 and May 2022. Total 85 patients with age range 10-80 years, with history of laryngopharyngeal symptoms and preoperative evaluation of thyroidectomy patients were selected. After getting detail history of flexible naso-pharyngo-laryngoscopy and findings were documented and analyzed. Under local anesthesia, spray in the nose and throat gargles. The laryngoscope passed through nose and nasopharynx into the laryngopharynx, and assessing all the structures. Data was analyzed through SPSS v 22. Results: The patients mean age was 28.96±9.14 years. Among all the patients 49(57.64%) were female and 36(42.3%) were male. The population highest percentage 26(30.5%) were 21-30 years old. The laryngeal complaint of hoarseness was highest with 38.8% indicated after flexible laryngoscope procedure according to other symptoms. According to diagnosis made on flexible laryngoscopy, the vocal nodules were highest with 15.3% detected. The diagnostic tools in diagnosis of laryngeal pathologies, its availability and cost effectiveness led to limited access of the patients to such sophisticated diagnostic procedure. Conclusion: Flexible laryngoscopy gives detailed visualization of the larynx and don’t leave the examiner inconclusive about laryngeal pathologies. Keywords: Clinical audit; Diagnostic equipment; Laryngoscopy; Nasopharyngeal diseases; Outpatient clinics, hospital.
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- 2023
169. The co-modification of MoS2 and CdS on TiO2 nanotube array for improved photoelectrochemical properties
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Ying Wang, Yuanyuan Kong, Ahmad Umar, Xiaofang Hong, and Mingxuan Sun
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Photocurrent ,Materials science ,business.industry ,Anodizing ,Open-circuit voltage ,General Chemical Engineering ,Tio2 nanotube ,General Engineering ,Physics::Optics ,General Physics and Astronomy ,Heterojunction ,Electron ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Electrochemistry ,Condensed Matter::Materials Science ,Physics::Atomic and Molecular Clusters ,Optoelectronics ,General Materials Science ,business ,Visible spectrum - Abstract
Herein, a heterostructure of MoS2/CdS/TiO2 nanotube arrays is constructed by successive ionic layer adsorption/reaction of CdS and dipping-assembly of MoS2 on the vertically oriented TiO2 nanotubes prepared by anodization method. The heterostructure is extensively investigated in terms of the composition, morphology, structural, and optical properties. It is observed that the co-modification of TiO2 nanotube arrays with CdS and MoS2 significantly enhances the visible light response and boosts the facile photo-generated electrons’ transfer and charge separation efficiencies. Therefore, the prepared heterostructure photo-anode exhibits significantly enhanced photoelectrochemical properties including photocurrent, open circuit potential, and photo-conversion efficiencies compared with that of pure TiO2 nanotube arrays and CdS/TiO2 nanotube systems. Interestingly, it is found that the MoS2 coatings on the surface of CdS/TiO2 nanotube arrays greatly enhance their photoelectrochemical stability. The presented work demonstrates that MoS2/CdS/TiO2 nanotube heterostructures are a promising material for improved photoelectrochemical properties. A heterostructure of MoS2/CdS/TiO2 nanotube arrays was constructed by successive ionic layer adsorption/reaction of CdS and dipping-assembly of MoS2 on the vertically oriented TiO2 nanotube arrays, and their improved photoelectrochemical properties were demonstrated
- Published
- 2021
170. Highly sensitive and selective 2-nitroaniline chemical sensor based on Ce-doped SnO2 nanosheets/Nafion-modified glassy carbon electrode
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Farid A. Harraz, Hassan Algadi, Ahmed Ibrahim, Rajesh Kumar, Mabkhoot A. Alsaiari, Mohammed Jalalah, Jahir Ahmed, Hasan Albargi, and Ahmad Umar
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Materials science ,Polymers and Plastics ,Materials Science (miscellaneous) ,Nanoparticle ,Chronoamperometry ,Tin oxide ,Dielectric spectroscopy ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Nafion ,Electrode ,Materials Chemistry ,Ceramics and Composites ,Cyclic voltammetry ,Nanosheet - Abstract
In this paper, pure SnO2 and Ce-doped SnO2 nanosheets were synthesized through a facile hydrothermal method. The synthesized materials were characterized by different techniques for their physico-chemical properties. The XRD data indicated the characteristic tetragonal rutile crystal phase for SnO2. Ce doping was ascertained by the presence of the diffraction peaks of CeO2 in all the doped samples of the SnO2 nanosheets. FESEM images revealed highly rough surfaces as well as the agglomeration of a large number of small nanoparticles of multiple shapes to form nanosheets like morphologies for pure SnO2 and Ce-doped SnO2. Electrochemical techniques like cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry were applied to demonstrate the electrochemical performances of the pure SnO2 and Ce-doped SnO2 nanosheets/Nafion-modified glassy carbon electrode (GCE). The 3% Ce-doped SnO2 nanosheet/Nafion-modified GCE showed a remarkable sensitivity of 0.9986 μA μM−1 cm−2 over a linear dynamic range of 0.5–20.3 µM. The corresponding linear regression equation was Ip (μA) = 0.0709 [2-nitroaniline (μM)] + 0.1385 with R2 = 0.99325. The LOD of the modified sensor was found to be 6.3 ± 0.1 nM at the signal-to-noise ratio of S/N = 3. The newly developed sensor electrode exhibited good selectivity toward 2-nitroaniline in the presence of common interfering species. Fabrication and characterization of highly sensitive and selective 2-nitroaniline chemical sensor based on cerium-doped tin oxide nanosheets/Nafion-modified glassy carbon electrode.
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- 2021
171. Selective ethanol gas sensing performance of flower-shaped CuO composed of thin nanoplates
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Mabkhoot A. Alsaiari, Umesh T. Nakate, Hasan Albargi, Ahmad Umar, Turki Alsuwian, Hassan Algadi, Sotirios Baskoutas, Sandip Paul Choudhury, and Ahmed Ibrahim
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010302 applied physics ,Materials science ,Band gap ,Oxide ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,Chemical engineering ,0103 physical sciences ,symbols ,Ethanol fuel ,Electrical and Electronic Engineering ,Fourier transform infrared spectroscopy ,High-resolution transmission electron microscopy ,Spectroscopy ,Raman spectroscopy ,Monoclinic crystal system - Abstract
Ethanol is one of the volatile organic compounds as well as organic pollutants that is essentially to be monitored using high response sensors. Semiconducting metal oxide nanostructures can be the potential sensor material for high-performance ethanol sensing application. Herein, we present the fabrication and characterization of highly sensitive and selective ethanol gas sensor based on flower-shaped CuO composed of thin nanoplates synthesized by facile hydrothermal process. The prepared flower-shaped CuO was examined by various techniques viz FESEM, XRD, EDS, elemental mapping, HRTEM, SAED, UV-visible spectroscopy, FTIR spectroscopy, and Raman spectroscopy, which confirmed the high-density growth, monoclinic crystal structure, and optical band gap of ~2.5 eV. The fabricated resistive sensor device based on flower-shaped CuO, at optimum experimental conditions, i.e., 250 °C, 100 ppm ethanol concentration, exhibited a high sensing response of 241%, while, at 10 ppm of ethanol concentration, the response was observed to be 5%. The transient responses as well as the stability of the sensor were analyzed and reported here. The selectivity of CuO sensor device was studied for NO2, CO2, CO, and CH4 gases and remarkably it was seen that the developed gas sensor devices demonstrated outstanding selectivity toward ethanol gas. Finally, the gas response mechanism of the fabricated resistive ethanol gas sensor was explained on the basis of the ionosorption model.
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- 2021
172. Delineation of profoundly birefringent nonlinear photonic crystal fiber in terahertz frequency regime
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Sapana Yadav, Sachin Singh, Pooja Lohia, Ahmad Umar, and Dilip Kumar Dwivedi
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Electrical and Electronic Engineering ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics - Abstract
The photonic aspects of semiconducting hexagon-shaped photonic crystal fiber including effective mode area, effective mode index, dispersion, and confinement loss, have already been investigated. The finite element method has been used to compute the maximum distribution of the studied photonic crystal fiber by COMSOL software. The linear modifications from both the effective mode index and an effective mode area have been investigated. Dispersion and confinement loss are examined in terms of air hole ring number and wavelength. For every wavelength, the effective-index model implies that the studied fiber can indeed be single mode. Even though its practical single-mode range inside the opacity aperture of silica appears large, it is eventually confined by a bend-loss edge at both brief & medium wavelengths. Moreover, the reported fiber offers minimal confinement loss of almost 10−8 dB/cm, birefringence 0.0012, and dispersion around 10−11 ps/km nm.
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- 2022
173. Numerical Study to Enhance the Sensitivity of a Surface Plasmon Resonance Sensor with BlueP/WS2-Covered Al2O3-Nickel Nanofilms
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null Shivangani, Maged F. Alotaibi, Yas Al-Hadeethi, Pooja Lohia, Sachin Singh, D. K. Dwivedi, Ahmad Umar, Hamdah M. Alzayed, Hassan Algadi, and Sotirios Baskoutas
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General Chemical Engineering ,surface plasmon resonance sensor ,blue-phosphorus tungsten di-sulfide ,Al2O ,nickel ,sensitivity ,General Materials Science - Abstract
In the traditional surface plasmon resonance sensor, the sensitivity is calculated by the usage of angular interrogation. The proposed surface plasmon resonance (SPR) sensor uses a diamagnetic material (Al2O3), nickel (Ni), and two-dimensional (2D) BlueP/WS2 (blue phosphorous-tungsten di-sulfide). The Al2O3 sheet is sandwiched between silver (Ag) and nickel (Ni) films in the Kretschmann configuration. A mathematical simulation is performed to improve the sensitivity of an SPR sensor in the visible region at a frequency of 633 nm. The simulation results show that an upgraded sensitivity of 332°/RIU is achieved for the metallic arrangement consisting of 17 nm of Al2O3 and 4 nm of Ni in thickness for analyte refractive indices ranging from 1.330 to 1.335. The thickness variation of the layers plays a curial role in enhancing the performance of the SPR sensor. The thickness variation of the proposed configuration containing 20 nm of Al2O3 and 1 nm of Ni with a monolayer of 2D material BlueP/WS2 enhances the sensitivity to as high as 374°/RIU. Furthermore, it is found that the sensitivity can be altered and managed by means of altering the film portions of Ni and Al2O3
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- 2022
- Full Text
- View/download PDF
174. Carbon Dots derived from Ocimum sanctum for dapsone–protein interactions: a quantitative approach
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Anjali Vijeata, Ganga Ram Chaudhary, Savita Chaudhary, Ahmad Umar, and Sotirios Baskoutas
- Published
- 2022
175. Development of mobile billing application system for PAMDES water meter data logging
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Ahmad, Umar Ali, primary, Ramdani, Ikbal, primary, Isham, Fath Muhammad, primary, Septiawan, Reza Rendian, primary, Setiady, R Rogers Dwiputra, primary, Rusdinar, Angga, primary, Dinimaharawati, Ashri, primary, Pratama, Yusup Diva, primary, Sofyan, Fauzi, primary, and Alam, Rifdo Shah, primary
- Published
- 2022
- Full Text
- View/download PDF
176. The Effect of Force Ratio Multiplier on A Control System for Surfing Problem Simulation
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Septiawan, Reza Rendian, primary, Virgono, Agus, additional, Ahmad, Umar Ali, additional, Abadi, Prayitno, additional, and Saputra, Mas'ud Adhi, additional
- Published
- 2022
- Full Text
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177. Evaluation of EN2 gene as a potential biomarker for bladder cancer
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Aldoghachi, Ahmed Faris, primary, Baharudin, Aminuddin, additional, Ahmad, Umar, additional, Choy, Chan Soon, additional, Aik, Ong Ting, additional, Yunus, Rosna, additional, Razack, Azad, additional, Yusoff, Khatijah, additional, and Veerakumarasivam, Abhi, additional
- Published
- 2022
- Full Text
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178. Search engine optimisation (SEO) strategy as determinants to enhance the online brand positioning
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Ahmad, Umar Faruq, primary, Mahdee, Junainah, additional, and Abu Bakar, Normazalila, additional
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- 2022
- Full Text
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179. Knowledge, Attitude and Practices Toward Coronavirus Disease (COVID- 19) in Southeast and South Asia: A Mixed Study Design Approach
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Rahman, Mohammad Meshbahur, primary, Marzo, Roy Rillera, additional, Chowdhury, Shanjida, additional, Qalati, Sikandar Ali, additional, Hasan, Mohammad Nayeem, additional, Paul, Gowranga Kumar, additional, Abid, Khadijah, additional, Sheferaw, Wegayehu Enbeyle, additional, Mariadass, Angela, additional, Chandran, Divitra, additional, Kanan, Shasvini, additional, Firdaus, Ahmad Umar Shafie Bin Ahmad, additional, Sabarin, Fatimah Az Zahra' binti, additional, and Lin, Yulan, additional
- Published
- 2022
- Full Text
- View/download PDF
180. Facile microwave synthesis of tungsten-doped PbI2 nanostructures for optoelectronic and radiation detection devices
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T.H. AlAbdulaal, V. Ganesh, S.G.S. Al-Amri, H.Y. Zahran, H. Algarni, Ahmad Umar, Hasan B. Albargi, I.S. Yahia, and M.A. Ibrahim
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Mechanics of Materials ,Mechanical Engineering ,General Materials Science ,Condensed Matter Physics - Published
- 2023
181. Career shift and career services in college
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Muhammad Munadi and Ahmad Umar
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Service (business) ,Medical education ,Qualitative analysis ,ComputingMilieux_THECOMPUTINGPROFESSION ,Formal education ,ComputingMilieux_COMPUTERSANDEDUCATION ,Face (sociological concept) ,Christian ministry ,Psychology ,Competence (human resources) ,Career development ,Research method - Abstract
This study aims to determine the relationship between independent competency standards of students with career development, career shift trends, and the relationship between extracurricular activities and student career development in College. This research method uses document studies about the ins and outs of career development in College. I collected documents from the Guidance and Counseling Implementation Guidelines in Formal Education published by the Directorate General of Teachers and Education Personnel of the Ministry of Education and Culture in 2016, publications related to career development, and publications from McKinsey. It analyzed the data using descriptive qualitative analysis. The result of this research is that the standard of self-reliance competence has been optimized integratively by institutions in College through career service activities. These activities are extracurricular, co-curricular, extracurricular cooperation between lecturers. It can carry activities in College to prepare students to face the trend of shifting community careers at the local, national, and global levels.
- Published
- 2021
182. Ni Foam Substrates Modified with a ZnCo2O4 Nanowire-Coated Ni(OH)2 Nanosheet Electrode for Hybrid Capacitors and Electrocatalysts
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Ahmad Umar, Depeng Zhao, Xiang Wu, Hamed Algarni, Meizhen Dai, Xiaofei Zhu, and Hengqi Liu
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Capacitor ,Electrode material ,Nanostructure ,Materials science ,law ,Electrode ,Nanowire ,General Materials Science ,Nanotechnology ,Energy storage ,Nanosheet ,law.invention - Abstract
For the construction of high-performance energy storage and conversion devices, the development of advanced electrode materials with specific nanostructural characteristics is a requirement of the ...
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- 2021
183. Stacked patch antenna with wider impedance bandwidth and high interport isolation for 2.4 GHz IBFD transceiver
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Haq Nawaz and Ahmad Umar Niazi
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Patch antenna ,Computer science ,business.industry ,020208 electrical & electronic engineering ,Impedance bandwidth ,0202 electrical engineering, electronic engineering, information engineering ,Electrical engineering ,020206 networking & telecommunications ,02 engineering and technology ,Isolation (database systems) ,Electrical and Electronic Engineering ,Transceiver ,business - Abstract
This paper reports a bi-port, wideband, parasitic-fed, single/shared patch antenna with enhanced interport isolation for 2.4 GHz in-band full duplex (IBFD) applications. The employed parasitic feeding provides comparatively the wider impedance bandwidth and better gain for the presented antenna. The improved self-interference cancellation (SIC) levels across the required bandwidth are obtained through differentially-driven receive (Rx) mode operation. The differential Rx operation performs effective cancellation of in-band self-interference (SI) through signal inversion mechanism to achieve the additional isolation on the top of the intrinsic isolation of polarization diversity. The validation model for the presented antenna features ≥88 dB peak isolation between the dual-polarized Tx and Rx ports. In addition, the measured Tx–Rx isolation for prototype is >70 dB across the 10 dB return loss bandwidth of 100 MHz (2.42–2.52 GHz). The measured gain for each mode is better than 7.0 dBi. The novelty of this work is that compared to previously reported designs, the presented antenna offers wider impedance bandwidth and improved SIC levels in addition to superior gain performance. To the best of our knowledge, this is the first single/shared patch antenna which provides better than 70 dB interport isolation across the 10 dB return loss bandwidth of 100 MHz along with 7.0 dBi gain for Tx/Rx modes.
- Published
- 2021
184. Changing Patterns of Temperature in Yobe State, North-Eastern Nigeria: An Evidence of Climate Change
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O. Musa Kehinde, A. Ahmad Umar, and Bulama Lawan
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Geography ,State (polity) ,media_common.quotation_subject ,Climate change ,General Medicine ,Physical geography ,media_common - Abstract
Air temperature is one of the fundamental indicators of Climate Change in any place on earth. Understanding the changing patterns of air temperature in Yobe State is instrumental in establishing the manifestation of Climate Change in the area and to enables the policy makers to design the best mechanisms to cope with the vagaries of increasing temperature. This study examined the changing patterns of temperature in Yobe State as an evidence of Climate Change. The study used mean monthly minimum and maximum air temperature data collected from the archives of the Nigerian Meteorological Agency (NIMET) with respect to Nguru and Potiskum weather stations in the State for a period of 1956-2015. The data was analyzed using descriptive statistics, linear regression trend lines and coefficient of variation (C.V). The result showed that April is the hottest month with the highest mean maximum temperatures of 39.6°C and 38.6°C in Nguru and Potiskum respectively while January is the coldest month with mean temperatures of 30.5°C and 30.8°C for Nguru and Potiskum respectively. Further finding revealed that temperatures are highly variable in February in both Nguru and Potiskum with C.V of 8.7% and 5.7% and less variable in October with C.V of 2.0%. Finding showed that in general term, there were upward trends in monthly and annual positive temperature anomalies ranging from 0.2°C to as high as 4.0°C in some months and years in the state. The study concludes that temperatures in Yobe State have witnessed series of changes within the 60 years period. Therefore, it is suggested that stakeholders in the Yobe State Environmental Protection Agency should intensify efforts in reducing deforestation while encouraging people on afforestation with a view to reducing the impact of Greenhouse gases that are contributing to more warming than normal. There should be adequate electricity and water supply for immediate relieve from excessive heat emanating from high temperature.
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- 2021
185. Star-Fruit-Shaped CuO Structures for High Performance Ethanol Gas Sensor Device
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Sotirios Baskoutas, Hasan Albargi, Hassan Algadi, Mohsen A. M. Alhamami, Rajesh Kumar, Umesh T. Nakate, Ahmed Ibrahim, and Ahmad Umar
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Materials science ,020401 chemical engineering ,Chemical engineering ,General Materials Science ,Ethanol fuel ,02 engineering and technology ,010501 environmental sciences ,0204 chemical engineering ,Star (graph theory) ,01 natural sciences ,0105 earth and related environmental sciences - Abstract
In this paper, star-fruit-shaped CuO microstructures were hydrothermally synthesized and subsequently characterized through different techniques to understand morphological, compositional, structural, crystal, optical and vibrational properties. The formation of star-fruit-shaped structures along with some polygonal and spherical nanostructures was confirmed by FESEM analysis. XRD data and Raman spectrum confirmed the monoclinic tenorite crystalline phase of the CuO with crystal size 17.61 nm. Star-fruit-shaped CuO microstructures were examined for ethanol gas sensing behavior at various operating temperatures and concentrations. The gas response of 135% was observed at the optimal temperature of 225 °C. Due to excellent selectivity, stability and re-usability, the as-fabricated sensor based on star-fruit-shaped CuO micro-structures may be explored for future toxic gas sensor applications.
- Published
- 2021
186. Investigating the optimum parameters of a negative photoresist to prepare a V-grooved diffraction grating on Si using photolithography and reactive ion etching techniques
- Author
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Mohammad Shahnawaze Ansari, Ahmad Umar, A. Al-Mujtabi, A. M. Abdel-Daiem, Alaa Y. Mahmoud, F. Al-Marzouki, and Yas Al-Hadeethi
- Subjects
Materials science ,Silicon ,chemistry.chemical_element ,02 engineering and technology ,Substrate (electronics) ,Photoresist ,01 natural sciences ,law.invention ,law ,Etching (microfabrication) ,0103 physical sciences ,Materials Chemistry ,Reactive-ion etching ,010302 applied physics ,Spin coating ,business.industry ,Process Chemistry and Technology ,021001 nanoscience & nanotechnology ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Volumetric flow rate ,chemistry ,Ceramics and Composites ,Optoelectronics ,Photolithography ,0210 nano-technology ,business - Abstract
In this study, the deposition parameters of the SU8 2000.5 negative photoresists have been investigated and optimized for the photolithographic technique. Then, applied the inductive coupled plasma reactive ion etching (ICP RIE) to produce V-shaped groove diffraction grating on a silicon substrate. Spin coater (speed: 1000 rpm) was used to coat the photoresist over the Si substrate. The observed photoresist film thickness was measured by ellipsometry and found to be 800 nm. Interestingly, the film exhibited some stability with increasing the spin speed. The thermogravimetric analysis was used to optimize the baking temperature which was found to be ~105 °C. Contrast curves were obtained experimentally and used to optimize the exposure energy along with the images obtained from the field emission scanning electron microscopy (FESEM). The optimized energy fluence was found to be 17 mJ/cm2. It was interesting to observe that the thickness of the photoresists film was increasing with the elevation of the exposure energy fluence. The FESEM images were used to optimize the ICP RIE etching process and the best etching conditions for the Si substrate were ICP power: 150 W, bias power: 100 W, and SF6 gas flow rate: 32 SCCM (standard cubic centimeters per minute), O2 gas flow: 8 SCCM, and Ar gas flow of 8 SCCM. It is worth to mention that well-defined V-shaped grooves were observed with a depth of 2 μm under the same experimental conditions.
- Published
- 2021
187. Methylene blue intercalated layered MnO2 nanosheets for high-sensitive non-enzymatic ascorbic acid sensor
- Author
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Elayaperumal Manikandan, Ahmad Umar, Ahmed Ibrahim, Ayyar Manikandan, P. Paulraj, Kannaiyan Pandian, K. Rajendran, Sotirios Baskoutas, A. Sathamraja, Rajesh Kumar, Mabkhoot A. Alsaiari, and Hassan Algadi
- Subjects
010302 applied physics ,Tetramethylammonium hydroxide ,Materials science ,Chronoamperometry ,Condensed Matter Physics ,Ascorbic acid ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Crystallinity ,chemistry ,0103 physical sciences ,Dehydroascorbic acid ,Electrical and Electronic Engineering ,Fourier transform infrared spectroscopy ,Cyclic voltammetry ,Methylene blue ,Nuclear chemistry - Abstract
Methylene blue intercalated layered MnO2 nanosheets (MB-MnO2) were synthesized through an ex-situ method at room temperature. Tetramethylammonium hydroxide (TMAOH) was used as a delaminating agent for the synthesis of nanosheet-like structures of MnO2. The prepared nanocomposites were analyzed by various instrumental techniques such as UV–visible, FTIR, XRD, FESEM, and EDX for the close examination of the morphology, structure, shape, crystallinity, and vibrational characterization. Typical two-dimensional layer sheet-like morphologies with multiple folds were observed for non-intercalated MnO2, whereas intercalated MnO2 showed more flattered and planar square-shaped and elongated ultrathin sheet-like structures with occasional folds and crinkles. MB intercalated MnO2nanosheets were used as an efficient electron mediator for the electrooxidation of the ascorbic acid to dehydroascorbic acid. Cyclic voltammetry and chronoamperometry confirmed the excellent electrocatalytic activity of the modified MB intercalated MnO2 nanosheets/GCE over a wide range of ascorbic acid concentrations in 0.1 M PBS. The detection limit was computed to be 0.05 μM. The effect of the scan rates and concentration of the ascorbic acid were also analyzed.
- Published
- 2021
188. Ni-Doped ZnO Thin Films: Deposition, Characterization and Photocatalytic Applications
- Author
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Abdulaziz Ali Alghamdi, Ahmad Umar, C. Gopinathan, K. Moorthy, N. P. Lalla, Rajesh Kumar, S.S.R. Inbanathan, and D. Rani Rosaline
- Subjects
Materials science ,Scanning electron microscope ,Doping ,Biomedical Engineering ,Bioengineering ,General Chemistry ,Substrate (electronics) ,Condensed Matter Physics ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Methyl orange ,Photocatalysis ,General Materials Science ,Crystallite ,Thin film ,Wurtzite crystal structure - Abstract
Root like structured Ni-doped zinc oxide [Zn(1-x)NixO (x = 0.09)] thin films were deposited on a non-conducting glass substrate by indigenously developed spray pyrolysis system at optimized substrate hotness of 573±5 K. Thus obtained Ni-doped ZnO thin films were characterized by UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Atomic Force Microscopy (AFM). XRD result revealed that Ni-doped ZnO has a polycrystalline nature with a hexagonal wurtzite structure. For pure ZnO and Ni-doped ZnO thin films, the particle sizes were 60.9 and 53.3 nm while lattice strain values were 1.56×10−3 and 1.14×10−3, respectively. The film surface showed characteristic root-like structure as observed by the SEM. It was observed that the Ni-doped ZnO thin films were grown in high density along with more extent of branching as compared to pure ZnO thin films but retained the root-like morphologies, however, the branches were more-thinner and of shorter lengths. AFM analysis showed that the surface grains of the Ni-doped samples are homogeneous with less RMS roughness values compared with the undoped ZnO samples. The photocatalytic activity of the prepared thin films was evaluated by the degradation of methyl orange (MO) dye under UV light irradiation. Pure ZnO and Ni-doped ZnO thin films took 150 min and 100 min to degrade about 60% MO dye, respectively.
- Published
- 2021
189. ZnO–SnO2 nanocubes for fluorescence sensing and dye degradation applications
- Author
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Ahmad Umar, Yas Al-Hadeethi, Rajesh Kumar, Mohinder Singh Chauhan, and Ramesh Kumar
- Subjects
010302 applied physics ,Photoluminescence ,Materials science ,Process Chemistry and Technology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Fluorescence ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Tetragonal crystal system ,X-ray photoelectron spectroscopy ,chemistry ,0103 physical sciences ,Materials Chemistry ,Ceramics and Composites ,Photocatalysis ,Methyl orange ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Spectroscopy ,Nuclear chemistry - Abstract
ZnO–SnO2 nanocubes were used as promising material for efficient sensing of p-nitrophenol and faster photocatalytic degradations of dyes like methyl orange (MO), methylene Blue (MB) and acid orange 74 (AO74). ZnO–SnO2 nanocubes were prepared by the facile solution process at 50 °C using Zn(NO3)2·6H2O and SnCl2·2H2O as a precursor in the presence of ethylenediammine. The synthesized material was examined for its morphological, structural, crystalline, optical, vibrational, and compositional studies by using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy. FESEM studies revealed the formation of well-defined ZnO–SnO2 nanocubes where the structural examinations revealed the formation of a crystalline tetragonal rutile phase for SnO2 with some crystal sites doped with Zn. The as-synthesized nanocubes were explored for their photocatalytic activities towards three different dye viz. MO, MB, and AO74. Practically, complete degradation of AO74 was seen within 4 minutes of photo-irradiation in the presence of 0.05 g ZnO–SnO2 nanocubes. However, 97.17% and 41.63% degradations were observed for MB and MO within 15 and 60 minutes, respectively. All the dye degradation processes followed the pseudo-first-order kinetic model. Moreover, the as-synthesized nanocubes were utilized to fabricate highly sensitive and selective fluorescent chemical sensor for the detection of p-nitrophenol (PNP). ZnO–SnO2 nanocubes showed a very low detection limit of 4.09 μM for the detection of PNP as calculated according to the 3σ IUPAC criteria. Further, the as-synthesized ZnO–SnO2 nanotubes were found to be highly selective for p-nitrophenol as compared to the other two isomers.
- Published
- 2021
190. In-vitro cytotoxicity of nickel oxide nanoparticles against L-6 cell-lines: MMP, MTT and ROS studies
- Author
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Renu Bala, Bhawna Pareek, Ahmad Umar, Saroj Arora, Davinder Singh, Ashun Chaudhary, Abdulrab Ahmed M. Alkhanjaf, Abdulrhman A. Almadiy, Hassan Algadi, Raman Kumar, Vivek Sheel Jaswal, and Sotirios Baskoutas
- Subjects
Nickel ,Plant Extracts ,Animals ,Metal Nanoparticles ,Nanoparticles ,Antineoplastic Agents ,Reactive Oxygen Species ,Biochemistry ,General Environmental Science ,Rats - Abstract
In the present work we synthesize nickel oxide nanoparticles (NiO NPs) using Rhododendron arboretum (flower) (RNi), Tinospora cordifolia (stems) (GNi), Corylus jacquemontii (seeds) (CNi), and Nardostachys jatamansi (roots) (NNi) extracts by co-precipitation method. The synthesized NiO NPs were characterized in detail in terms of their morphological, crystalline nature, structural and antiproliferative activity against rat skeletal myoblast (L-6) cell lines. Morphological studies confirmed the formation of nanoparticles, while the structural and compositional characterization revealed the well-crystallinity and high purity of the synthesized nanoparticles. For biological applications and cytotoxicity examinations of the synthesized NPs, the rat skeletal myoblast (L-6) cell lines were subjected to study. By detailed cytotoxic investigations, it was observed that among the four kinds of NiO NPs prepared through different plant extracts, the Tinospora cordifolia (stems) showed strong antiproliferative activity against rat skeletal myoblast (L-6) cell lines and the calculated IC
- Published
- 2022
191. Visible-light driven excellent photocatalytic degradation of ofloxacin antibiotic using BiFeO
- Author
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Girish, Gupta, Sushil K, Kansal, Ahmad, Umar, and Sheikh, Akbar
- Abstract
The extensive exploration of multiferroic materials for degradation of contaminants and environmental remediation is promptly strengthened because of their distinct applications. BiFeO
- Published
- 2022
192. Highly Sensitive and Selective Sulfite Ion Sensor Based on Biochemically Stable Iodo‐Functionalized Coumarin Fluorophores
- Author
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Aman K. K. Bhasin, Pooja Chauhan, Savita Chaudhary, Ahmad Umar, and Sotirios Baskoutas
- Subjects
General Chemistry - Published
- 2022
193. Highly fluorescent nickel based metal organic framework for enhanced sensing of Fe
- Author
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Jasjot, Kaur, Manjot, Kaur, Sushil Kumar, Kansal, Ahmad, Umar, and Hassan, Algadi
- Subjects
Nickel ,Cations ,Water ,Metal-Organic Frameworks ,Fluorescent Dyes - Abstract
Heavy metal contamination has sparked widespread concern among the populace. The significant issues necessitate the creation of high-performance fluorescent pigments that can identify harmful elements in water. The present study deals with metal organic framework [MOF] based on nickel [Ni-BDC MOF]. The Ni-BDC MOF was prepared by facile solvothermal method using nickel nitrate hexahydrate and terephthalic acid ligand as precursors. The MOF was characterized by various techniques in order to examine the crystal, morphological, structural, composition, thermal and optical properties. The detailed characterizations revealed that the synthesized Ni-BDC MOF are well-crystalline with high purity and possessing 3D rhombohedral microcrystals with rough surface. The MOF demonstrate good luminescence performance and excellent water stability. According to the Stern Volmer plot, the tests set up under optimized conditions demonstrate a linear correlation between the fluorescence intensity and concentration of both ions, i.e. Fe
- Published
- 2022
194. High-sensitive ferrocene labeled aptasensor for the detection of Mucin 1 by tuning the sequence constitution of complementary probe
- Author
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Chengxian Zhao, Wenjuan Guo, Ahmad Umar, Hassan Algadi, Meishan Pei, Ahmed A. Ibrahim, Xueying Yang, Zhe Ren, Xiangyun Mi, and Luyan Wang
- Subjects
Limit of Detection ,Metallocenes ,Mucin-1 ,Electrochemical Techniques ,Aptamers, Nucleotide ,Analytical Chemistry - Abstract
A strand displacement-based "signal-off" electrochemical aptasensor is reported for the detection of Mucin 1 (MUC 1) based on a high original signal. Different from the conventional "signal-off" electrochemical biosensors where electrochemical substances are dispersed in electrolyte solution, here the current signal was generated by the complementary probe (CP) associated with ferrocene (Fc) labeled aptamer (Apt.-Fc). Because Apt.-Fc and MUC 1 have a higher affinity, Apt.-Fc dissociates from CP in the presence of MUC 1, resulting in a reduction of detection current signal generated by oxidation of labeled Fc. In this system, high detection signal is necessary to improve the sensor's performance. For this aim, a strategy is proposed for changing the modalities of electron transport and the quantity of Apt.-Fc introduced by simply tuning the sequence constitution of CP. As expected, a high detection current signal was obtained after selecting CP(Apt.-Fc)-TTT as the optimal CP. The aptasensor was then employed to detect MUC 1, and satisfactory detection results with a low detection limit (LOD) of 0.087 pM (S/N = 3), good specificity, good stability, and feasibility of detection of MUC 1 in artificial serum (recovery of 92-101%, RSD of 1.36-5.23%) were obtained.
- Published
- 2022
195. Application of Addawa’ul Humma Preparation for the Treatment of Typhoid Fever
- Author
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Ahmad Umar faruk, Yahaya Rabiu R A, Ummu Rabiu R A, Iliyasu Mahmud Yerima, Nafiu Muhammad Wada, and Haruna Saidu
- Subjects
business.industry ,Medicine ,business ,medicine.disease ,Virology ,Typhoid fever - Abstract
The study assessed the efficacy of Addawa’ul humma for the treatment of typhoid fever. Addawau’l humma is a name given to a herbal preparation consisting of (Mango, Neem, Orange, Lemons, and Guava extract). The preparation was tested and compare with the standard drug Ciprofloxacin as control experiment. Results of phytochemical screening showed the presence of Alkaloid, Flavonoid, Tannins, Glycosides, Anthraquinone, Saponins and Steroid. There is no significance difference between Addawa’ul humma and the standard drug Ciproflxacin (P
- Published
- 2021
196. Effect of cerium ions in Ce-Doped ZnO nanostructures on their photocatalytic and picric acid chemical sensing
- Author
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Mohinder Singh Chauhan, Manoj Kumar, Ahmad Umar, and M. Shaheer Akhtar
- Subjects
010302 applied physics ,Materials science ,Dopant ,Process Chemistry and Technology ,Doping ,chemistry.chemical_element ,Picric acid ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Catalysis ,Cerium ,chemistry.chemical_compound ,chemistry ,0103 physical sciences ,Materials Chemistry ,Ceramics and Composites ,Photocatalysis ,Methyl orange ,0210 nano-technology ,Wurtzite crystal structure ,Nuclear chemistry - Abstract
Nanostructured ZnO doped with different Ce precursor concentrations (1, 5 and 10 mol%) has been prepared via co-precipitation method and tested for their photocatalytic and chemical sensing performances toward methyl orange (MO) and picric acid (PA) chemicals, respectively. After addition of Ce dopant, the spherical morphology of ZnO particles changed to a cone-like structure and exhibited the single-phase wurtzite structure, except for the 10 mol % dopant concentration. Blue-shift was detected in 5 mol% Ce doping, and this was found to be the optimum concentration for achieving the maximum dye degradation and sensing performances. The 5 mol% Ce doped ZnO expressed the complete MO degradation under UV light illumination, but the decrease in MO degradation with 10 mol% Ce doped ZnO was suggested to suppress the Ce3+ character in the sample. Facile redox couple Ce3+/Ce4+ appeared to improve the charge separation of Ce-doped ZnO upon UV illumination, forming the basis for release of O2, leading to increased catalytic and PA sensing performances.
- Published
- 2021
197. Realizing high performance flexible supercapacitors by electrode modification
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Tong Xia, Depeng Zhao, Qing Xia, Ahmad Umar, and Xiang Wu
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General Chemical Engineering ,General Chemistry - Abstract
We prepare hybrid structured NiCo2S4@PPy nanoarchitectures by a hydrothermal method and subsequent electrodeposition process. The assembled asymmetric device presents an energy density of 59.59 W h kg−1 at 1404.04 W kg−1.
- Published
- 2021
198. Practical room temperature formaldehyde sensing based on a combination of visible-light activation and dipole modification
- Author
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Ahmad Umar, Nicolaas Frans de Rooij, Lanpeng Guo, Yao Wang, Huiyun Hu, Nengjie Cao, Hao Li, Guofu Zhou, Hamed Algarni, and Hongping Liang
- Subjects
Detection limit ,Nanocomposite ,Materials science ,Renewable Energy, Sustainability and the Environment ,Graphene ,Analytical chemistry ,Formaldehyde ,Nanoparticle ,Charge density ,General Chemistry ,law.invention ,Dipole ,chemistry.chemical_compound ,chemistry ,law ,General Materials Science ,Visible spectrum - Abstract
Implementing sensitive and fast ppb-level formaldehyde sensing at room temperature is still in extreme demand for practical indoor air quality monitoring. Herein, we developed a visible-light-sensitive and dipole-modified graphene-based nanocomposite ZnOx@ANS-rGO for ultrasensitive trace formaldehyde sensing. The rich oxygen vacancy zinc oxide (ZnOx) nanoparticles on graphene nanosheets provide OH-groups and edge sorption sites to facilitate the activation of adsorbed oxygen. Moreover, the supramolecular assembled 5-aminonaphthalene-1-sulfonic acid-modified graphene (ANS-rGO) nanosheets with donor–π–acceptor dipole served as an excellent conduction platform to transport and collect photo-generated electrons. Based on the collaboration of rich ZnOx and ANS-rGO, the obtained sensor ZnOx@ANS-rGO-0.1 showed the highest response (Ra/Rg = 1.58 to 1 ppm HCHO) among the MOS materials reported so far, and its limit of detection (LOD) can be as low as 5 ppb under 405 nm light illumination at RT. The outstanding efficiency and accuracy of the obtained gas sensor were confirmed by practical performance estimation in a 30 m3 chamber. The selectivity, long-term stability, repeatability and humidity resistance of the obtained sensors at RT were also revealed. The sensing mechanism based on the combination of visible-light activation and dipole modification was analyzed by the O-XPS, PL, in situ ATR-FTIR and charge density difference calculation.
- Published
- 2021
199. Clinical outcome of Montelukast Sodium in Children with Adenoid Hypertrophy
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Naveed Arshad, Syed Ali Naqi, Ahmed Hassan Ashfaq, Jais Kumar Karmani, and Mumtaz Ahmad Umar
- Subjects
0301 basic medicine ,Pediatrics ,medicine.medical_specialty ,medicine.medical_treatment ,030106 microbiology ,Mouth breathing ,Adenoid ,Placebo ,Muscle hypertrophy ,03 medical and health sciences ,0302 clinical medicine ,Adenoidectomy ,030225 pediatrics ,medicine ,business.industry ,General Medicine ,Hypertrophy ,medicine.disease ,Tonsillectomy ,Montelukast sodium ,stomatognathic diseases ,Obstructive sleep apnea syndrome ,medicine.anatomical_structure ,Montelukast Sodium ,Original Article ,medicine.symptom ,business ,Adenoid hypertrophy - Abstract
Background & Objectives: Generally, the blockage of upper respiratory tract in children is seen with the hypertrophy of adenoids and tonsils. Normally for patients with adenoid hypertrophy (AH), Adenoidectomy with or without Tonsillectomy is carried out, however it has its own complications like haemorrhage and recurrence of adenoid tissue. Consequently, therapeutic approach has increased extraordinary consideration rather than surgical procedure. The inflammatory process proposed for AH has prompted the utilization of anti-inflammatory drugs to treat this issue. The objective of this study was to assess the impacts of Montelukast sodium in children with enlarged adenoids. Methods: A randomized controlled trail was performed from April 2018 to March 2019 in the Otorhinolaryngology clinic of Dr. Akbar Niazi Teaching Hospital, Islamabad. In this randomized, placebo treatment-controlled trial, 60 children aged 4-12 years meeting inclusion criteria were isolated into two groups. The study group was treated with Montelukast sodium 5mg consistently for three months while the control group got placebo treatment for a similar timeframe. A questionnaire was filled by parents/ guardians of every child before and after the intervention to evaluate the severity of sleep discomfort, snoring and mouth breathing. Results: Following 3 months of treatment, significant reduction in size of the adenoids was seen in 76% of study group compared with just 3% of control group getting placebo treatment. Conclusion: Montelukast sodium seems to be effective in the reduction of the size of adenoids and improvement in clinical manifestations. It can be viewed as a viable option in contrast to surgical treatment in children with hypertrophy of adenoids. doi: https://doi.org/10.12669/pjms.37.2.2670 How to cite this:Naqi SA, Ashfaq AH, Umar MA, Karmani JK, Arshad N. Clinical outcome of Montelukast Sodium in Children with Adenoid Hypertrophy. Pak J Med Sci. 2021;37(2):362-366. doi: https://doi.org/10.12669/pjms.37.2.2670 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
- Published
- 2021
200. Direct Growth of Flower-Shaped ZnO Nanostructures on FTO Substrate for Dye-Sensitized Solar Cells
- Author
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Ahmad Umar, Mohammad Shaheer Akhtar, Tubia Almas, Ahmed Abdulbaqi Ibrahim, Mohammed Sultan Al-Assiri, Yoshitake Masuda, Qazi Inamur Rahman, and Sotirios Baskoutas
- Subjects
Flower-shaped ZnO structures ,FTO substrate ,Dye-sensitized solar cells: Photovoltaics ,Crystallography ,QD901-999 - Abstract
The proposed work reports that ZnO nanoflowers were grown on fluorine-doped tin oxide (FTO) substrates via a solution process at low temperature. The high purity and well-crystalline behavior of ZnO nanoflowers were established by X-ray diffraction. The morphological characteristics of ZnO nanoflowers were clearly revealed that the grown flower structures were in high density with 3D floral structure comprising of small rods assembled as petals. Using UV absorption and Raman spectroscopy, the optical and structural properties of the ZnO nanoflowers were studied. The photoelectrochemical properties of the ZnO nanoflowers were studied by utilizing as a photoanode for the manufacture of dye-sensitized solar cells (DSSCs). The fabricated DSSC with ZnO nanoflowers photoanode attained reasonable overall conversion efficiency of ~1.40% and a short-circuit current density (JSC) of ~4.22 mA cm−2 with an open circuit voltage (VOC) of 0.615 V and a fill factor (FF) of ~0.54. ZnO nanostructures have given rise to possible utilization as an inexpensive and efficient photoanode materials for DSSCs.
- Published
- 2019
- Full Text
- View/download PDF
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