| 1. |
- Ahsan, Hajra, et al.
(författare)
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Photocatalysis and adsorption kinetics of azo dyes by nanoparticles of nickel oxide and copper oxide and their nanocomposite in an aqueous medium
- 2022
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Ingår i: PeerJ. - : PeerJ. - 2167-8359. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Azo dyes are recalcitrant organic pollutants present in textile industry effluents. Conventional treatment methods to remove them come with a range of disadvantages. Nanoparticles and their nanocomposites offer more efficient, less expensive and easy to handle wastewater treatment alternative. Methods. In this study, nanoparticles of nickel oxide (NiO-NPs), copper oxide (CuO-NPs) and their nanocomposite (NiO/CuO-NC) were synthesized using co- precipitation method. The functional groups present on the surface of synthesized nanomaterials were verified using Fourier-transform infrared spectroscopy (FTIR). Surface morphology was assessed using scanning electron microscopy (SEM) whereas purity, shape and size of the crystallite were determined using X-ray diffraction (XRD) technique. The potential of these nanomaterials to degrade three dyes i.e., Reactive Red-2 (RR-2), Reactive Black-5 (RB-5) and Orange II sodium salt (OII) azo dyes, was determined in an aqueous medium under visible light (photocatalysis). The photodegradation effectiveness of all nanomaterials was evaluated under different factors like nanomaterial dose (0.02-0.1 g 10 mL-1), concentration of dyes (20-100 mg L-1), and irradiation time (60-120 min). They were also assessed for their potential to adsorb RR-2 and OII dyes. Results. Results revealed that at optimum concentration (60 mgL-1) of RR-2, RB-5, and OII dyes, NiO-NPs degraded 90, 82 and 83%, CuO-NPs degraded 49, 34, and 44%, whereas the nanocomposite NiO/CuO-NC degraded 92, 93, and 96% of the said dyes respectively. The nanomaterials were categorized as the efficient degraders of the dyes in the order: NiO/CuO-NC > NiO-NPs > CuO-NPs. The highest degradation potential shown by the nanocomposite was attributed to its large surface area, small particles size, and quick reactions which were proved by advance analytical techniques. The equilibrium and kinetic adsorption of RR-2 and OII on NiO-NPs, CuO-NPs, and NiO/CuO-NC were well explained with Langmuir and Pseudo second order model, respectively (R2 ≥0.96). The maximum RR-2 adsorption (103 mg/g) was obtained with NiO/CuO-NC. It is concluded that nanocomposites are more efficient and promising for the dyes degradation from industrial wastewater as compared with dyes adsorption onto individual NPs. Thus, the nanocomposite NiO/CuO-NC can be an excellent candidate for photodegradation as well as the adsorption of the dyes in aqueous media.
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| 2. |
- Farooq, Muhammad, et al.
(författare)
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Thermodynamic Performance Analysis of Hydrofluoroolefins (HFO) Refrigerants in Commercial Air-Conditioning Systems for Sustainable Environment
- 2020
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Ingår i: Processes. - : MDPI. - 2227-9717. ; 8:2
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Tidskriftsartikel (refereegranskat)abstract
- Global warming is one of most severe environmental concerns that our planet is facing today. One of its causes is the previous generation of refrigerants that, upon release, remain in the atmosphere for longer periods and contribute towards global warming. This issue could potentially be solved by replacing the previous generation's high global warming potential (GWP) refrigerants with environmentally friendly refrigerants. This scenario requires an analysis of new refrigerants for a comparison of the thermodynamic properties of the previously used refrigerants. In the present research, a numerical study was conducted to analyze the thermodynamic performance of specifically low GWP hydrofluoroolefens (HFO) refrigerants for an actual vapor compression refrigeration cycle (VCRC) with a constant degree of 3 K superheat. The output parameters included the refrigeration effect, compressor work input, the coefficient of performance (COP), and the volumetric refrigeration capacity (VRC), all of which were calculated by varying the condenser pressure from 6 to 12 bars and vapor pressure from 0.7 to 1.9 bars. Results showed that R1234ze(Z) clearly possessed the desired thermodynamic performance. The drop in refrigeration effect for R1234ze(Z) was merely 14.6% less than that of R134a at a 12 bar condenser pressure; this was minimum drop among candidate refrigerants. The drop in the COP was the minimum for R1234ze(Z)-5.1% less than that of R134a at a 9 bar condenser pressure and 4.7% less than that of R134a at a 1.9 bar evaporator pressure, whereas the COP values of the other refrigerants dropped more drastically at higher condenser pressures. R1234ze(Z) possessed favorable thermodynamic characteristics, with a GWP of 7, and it can serve as an alternative refrigerant for refrigeration systems for a sustainable environment.
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| 3. |
- Ahsan, Ali, et al.
(författare)
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Formulation and evaluation of miconazole lipogel for enhanced drug permeation
- 2024
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Ingår i: Pakistan Journal of Pharmaceutical Sciences. - : UNIV KARACHI. - 1011-601X. ; 37:1, s. 95-105
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Tidskriftsartikel (refereegranskat)abstract
- Hydrophilic drugs could be incorporated into the skin surface by manes of Lipogel. This study aimed to prepare miconazole lipogel with natural ingredients to enhance drug permeability using dimethyl Sulfoxide (DMSO). The miconazole lipogels, A1 (without DMSO) and A2 (with DMSO) were formulated and evaluated for organoleptic evaluation, pH, viscosity, stability studies, freeze -thawing, drug release profile and drug permeation enhancement. Results had stated that prepared lipogel's pH falls within the acceptable range required for topical delivery (4 to 6) while both formulations show good results in organoleptic evaluation. The A2 formulation containing DMSO shows better permeation of miconazole (84.76%) on the artificial skin membrane as compared to A1 lipogel formulation (50.64%). In in -vitro drug release studies, A2 for-mulation showed 87.48% drug release while A1 showed just 60.1% drug release from lipogel. Stability studies were performed on model formulations under environmental conditions and both showed good spreadibility, stable pH, free of grittiness and good consistency in formulation. The results concluded that A2 formulation containing DMSO shows better results as compared to DMSO-free drug lipogel.
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| 4. |
- Akhtar, Muneeba, et al.
(författare)
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Response Surface Methodology (RSM) approach to formulate and optimize the bilayer combination tablet of Tamsulosin and Finasteride
- 2024
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Ingår i: Saudi Pharmaceutical Journal. - : Elsevier. - 1319-0164 .- 2213-7475. ; 32:3
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Tidskriftsartikel (refereegranskat)abstract
- An orally administered bilayer tablet with Tamsulosin (TAM) as the sustained release (SR) and Finasteride (FIN) as immediate release (IR) was manufactured. A response surface methodology was employed to formulate bilayer tablets with individual release layers, i.e., sustained and immediate release (SR and IR). Independent variables selected in both cases comprise hydroxypropyl methylcellulose (HPMC) as SR polymer, and avicel PH102 in the inner layer while Triacetin and talc in the outer layer, respectively. Tablets were prepared by direct compression, a total of 11 formulations were prepared for inner layer TAM, and 9 formulations for outer layer FIN were designed; these formulations were evaluated for hardness, friability, thickness, %drug content, and %drug release. A central composite design was employed in response surface methodology to design and optimize the formulation. The percentage of drug released was evaluated by in-vitro USP dissolution method of optimized formulation for 0.5, 2, and 6 hrs, and results were 24.63, 52.96, and 97.68 %, respectively. Drug release data was plotted in various kinetic models using a D.D solver, where drug release was first order that is concentration dependent and was best explained by Korsmeyer–Peppa kinetics, as the highest linearity was observed (R2 = 0.9693). However, a very close relationship was also noted with Higuchi kinetics (R2 = 0.9358). The mechanism of drug release was determined through the Korsmeyer model, and exponent "n" was found to be 0.4, indicative of an anomalous diffusion mechanism or diffusion coupled with erosion.
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| 5. |
- Asif, Muhammad, et al.
(författare)
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The Effect of Infrared Laser Irradiation on the Surface Morphology and Electrical Properties of Zinc Metal
- 2023
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Ingår i: Physchem. - : MDPI AG. - 2673-7167. ; 3:1, s. 22-33
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Tidskriftsartikel (refereegranskat)abstract
- This study details the irradiation of pure (99.995%) and immaculate metallic Zinc using Nd: YAG laser (1064 nm, 10 mJ, 9–14 ns). The influence and impact of multiple laser shots on the formation of microstructures and crystal structure orientations is assessed. Arrays of ablated craters are machined on the whole surface of the target to probe the electrical and topographical characteristics of laser-treated surfaces. Irradiated samples are examined by multiple characterizing techniques such as scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and a four-point probe for electrical conductivity measurements. SEM and AFM analysis exhibited the formation of laser-induced ripple structures with periodicity sheerly dependent on laser shots. A comparison of surface topography of the virgin and treated samples disclosed a pronounced modification in surface texture. The XRD patterns of laser shined targets indicate no momentous structural change in the crystal structure, whereas the measurements on the electrical conductivity of the irradiated surfaces exhibit an exponential descending trend with an augmentation in laser shots.
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| 6. |
- Irshad, Muneeb, et al.
(författare)
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Evaluation of BaCo0.Fe-4(0).4Zr0.2-xNixO3-delta perovskite cathode using nickel as a sintering aid for IT-SOFC
- 2021
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Ingår i: RSC Advances. - : Royal Society of Chemistry. - 2046-2069. ; 11:24, s. 14475-14483
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Tidskriftsartikel (refereegranskat)abstract
- In this research work, BaCo0.Fe-4(0).4Zr0.2-xNixO3-delta (x = 0, 0.01, 0.02, 0.03, 0.04) perovskite cathode material for IT-SOFC is synthesized successfully using a combustion method and sintered at low temperature. The effects of nickel as a sintering aid on the properties of BaCo0.Fe-4(0).Zr-4(0).O-2(3-delta) are investigated through different characterization methods. The addition of nickel increased the densification and grain growth at a lower sintering temperature 1200 degrees C. XRD analysis confirms a single phase of BaCo0.Fe-4(0).Zr-4(0).O-2(3-delta), and an increase in crystalline size is observed. SEM micrographs show formation of dense microstructure with increased nickel concentration. TGA analysis revealed that BaCo0.Fe-4(0).4Zr0.2-xNix cathode materials are thermally stable within the SOFC temperature range, and negligible weight loss of 2.3% is observed. The bonds of hydroxyl groups and metal oxides are confirmed for all samples through FTIR analysis. The highest electrical properties are observed for BaCo0.Fe-4(0).4Zr0.2-xNix (x = 0.04) due to increased densification and electronic defects compared to other compositions. The maximum power density of 0.47 W cm(-2) is obtained for a cell having cathode material BaCo0.Fe-4(0).4Zr0.2-xNix (x = 0.02) owing to its permeable and well-connected structure compared to others.
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| 7. |
- Iqbal, Muhammad Ahsan, et al.
(författare)
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MgAl-LDH/graphene protective film : Insight into LDH-graphene interaction
- 2020
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Ingår i: Surface & Coatings Technology. - : Elsevier. - 0257-8972 .- 1879-3347. ; 401
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Tidskriftsartikel (refereegranskat)abstract
- MgAl-layered double hydroxides (LDHs) thin films, exhibiting two distinct surface morphologies (Platelet and Cauliflower-like), were synthesized directly on the aluminum substrate. The as-prepared films were further modified with graphene due to the chemical inertness of graphene and its capability to act as a possible physical barrier against ionic media. The morphology and structure of MgAl-LDH/graphene composite films are fully characterized. The corrosion resistance properties were analyzed through Electrochemical impedance spectroscopy and the results were further fitted using “ZSimpWin” software to evaluate coating behavior. The graphene was found to interact with the LDH structure and provide another pathway for the corrosion reactions and results in improve LDHs corrosion resistance properties. The sealing effect of graphene resists the aggressive media penetration and caused an increase of one order magnitude in impedance modulus of MgAl-LDHs. The enhancement in corrosion resistance properties is attributed to the graphene impermeable behavior against corrosive species confirmed by physical and electrochemical characterizations.
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| 8. |
- Irshad, Muneeb, et al.
(författare)
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Evaluation of BaZr0.8X0.2 (X= Y, Gd, Sm) proton conducting electrolytes sintered at low temperature for IT-SOFC synthesized by cost effective combustion method
- 2020
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Ingår i: Journal of Alloys and Compounds. - : ELSEVIER SCIENCE SA. - 0925-8388 .- 1873-4669. ; 815
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Tidskriftsartikel (refereegranskat)abstract
- In present work, perovskite structured proton conducting electrolyte materials BaZr0.8Y0.2 (BZY), BaZr0.8Gd0.2 (BZGd) and BaZr0.8Sm0.2 (BZSm) synthesized by cost effective combustion method are investigated for intermediate temperature solid oxide fuel cell (IT-SOFC). The synthesized BZY, BZGd and BZSm materials are sintered at low temperature (1150 degrees C) and the effect of low sintering temperature on electrolyte properties are also explored. Microstructure, surface morphology, elemental composition, functional group and weight loss are studied using different characterization techniques like XRD, SEM, EDX, FTIR and TGA. XRD shows cubic perovskite structure of all synthesized materials. Secondary phase of Y2O3 is observed in BZY while BaO is observed in BZGd and BZSm due to low sintering temperature. SEM micrographs reveals dense microstructure of BZSm compared to BZY and BZGd. EDX analysis confirms the required material composition within all samples with no impurities. FTIR shows the presence of hydroxyl group and metal oxides and it is observed that BZY exhibit more structural symmetry compared to BZSm and BZGd. Highest conductivity observed (2.2 x 10(-3) S/cm) for BZY due to its structural symmetry and characteristic to prefer B-site of perovskite. Also significant power densities of 0.34 Wcm(-2), 0.24 Wcm(-2) and 0.32 Wcm(-2) for BZY, BZGd and BZSm electrolytes based cells at 650 degrees C implies that BZY, BZGd and BZSm can be used as IT-SOFC electrolytes. (C) 2019 Elsevier B.V. All rights reserved.
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| 9. |
- Khan, Muhammad Ahsan Iqbal, et al.
(författare)
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An Experimental and Comparative Performance Evaluation of a Hybrid Photovoltaic-Thermoelectric System
- 2021
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Ingår i: Frontiers in Energy Research. - : FRONTIERS MEDIA SA. - 2296-598X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- The majority of incident solar irradiance causes thermalization in photovoltaic (PV) cells, attenuating their efficiency. In order to use solar energy on a large scale and reduce carbon emissions, their efficiency must be enhanced. Effective thermal management can be utilized to generate additional electrical power while simultaneously improving photovoltaic efficiency. In this work, an experimental model of a hybrid photovoltaic-thermoelectric generation (PV-TEG) system is developed. Ten bismuth telluride-based thermoelectric modules are attached to the rear side of a 10 W polycrystalline silicon-based photovoltaic module in order to recover and transform waste thermal energy to usable electrical energy, ultimately cooling the PV cells. The experiment was then carried out for 10 days in Lahore, Pakistan, on both a simple PV module and a hybrid PV-TEG system. The findings revealed that a hybrid system has boosted PV module output power and conversion efficiency. The operating temperature of the PV module in the hybrid system is reduced by 5.5%, from 55 degrees C to 52 degrees C. Due to a drop in temperature and the addition of some recovered energy by thermoelectric modules, the total output power and conversion efficiency of the system increased. The hybrid system's cumulative output power increased by 19% from 8.78 to 10.84 W, compared to the simple PV system. Also, the efficiency of the hybrid PV-TEG system increased from 11.6 to 14%, which is an increase of 17% overall. The results of this research could provide consideration for designing commercial hybrid PV-TEG systems.
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| 10. |
- Khan, Yusra Habib, et al.
(författare)
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Parental Perceptions and Barriers towards Childhood COVID-19 Vaccination in Saudi Arabia : A Cross-Sectional Analysis
- 2022
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Ingår i: Vaccines. - : MDPI. - 2076-393X. ; 10:12
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The vaccination of children against Coronavirus disease (COVID-19) is a prime area of focus around the globe and is considered a pivotal challenge during the ongoing pandemic. This study aimed to assess parents ' intentions to vaccinate their children and the barriers related to pediatric COVID-19 vaccination. Methodology: An online web-based survey was conducted to recruit parents with at least one child under the age of 12 years from Saudi Arabia's Al-Jouf region. The parental intentions to vaccinate children were assessed via six items, while barriers against vaccination were assessed through seven items in validated study instrument. A 5-point Likert scale was used to record the responses of parents regarding both their intentions and barriers. Results: In total, 444 parents (28.41 +/- 7.4 years, 65% females) participated in this study. Almost 90% of parents were vaccinated against COVID-19 but only 42% of parents intended to vaccinate their children. The mean intention score was 2.9 +/- 1.36. More than one-third of study participants had no plan to vaccinate their children against COVID-19. The majority of the respondents agreed to vaccinate their children if vaccination was made compulsory by the government (relative index: 0.76, 73%). Out of seven potential barriers analyzed, concerns over vaccine safety and side effects were ranked highest (RII: 0.754), reported by 290 (65%) participants. In multivariate logistic regression, significant predictors of parental intention to vaccinate children were the increased education level of the parents (secondary education: OR = 3.617, p = 0.010; tertiary education: OR = 2.775, p = 0.042), COVID-19 vaccination status (vaccinated: OR = 7.062, p = 0.003), mother's involvement in decisions regarding the child's healthcare (mother: OR 4.353, p < 0.001; both father and mother: OR 3.195, p < 0.001) and parents' trust in the vaccine's safety (OR = 2.483, p = 0.022). Conclusions: This study underscored the low intention among parents to vaccinate their children against COVID-19. Vaccination intention was found to be associated with education, parents' vaccination status, the mother's involvement in healthcare decisions, and parents' trust in the vaccine's safety. On the other hand, parents' concerns over the safety and efficacy of the COVID-19 vaccine were widely reported as barriers to childhood vaccination. The health authorities should focus on addressing parental concerns about vaccines to improve their COVID-19 vaccination coverage.
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