| 1. |
- Abbas, Ghazanfar, et al.
(författare)
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Electrochemical investigation of mixed metal oxide nanocomposite electrode for low temperature solid oxide fuel cell
- 2017
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Ingår i: International Journal of Modern Physics B. - : WORLD SCIENTIFIC PUBL CO PTE LTD. - 0217-9792. ; 31:27
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Tidskriftsartikel (refereegranskat)abstract
- Zinc-based nanostructured nickel (Ni) free metal oxide electrode material Zn-0.60/CU0.20Mn0.20 oxide (CMZO) was synthesized by solid state reaction and investigated for low temperature solid oxide fuel cell (LTSOFC) applications. The crystal structure and surface morphology of the synthesized electrode material were examined by XRD and SEM techniques respectively. The particle size of ZnO phase estimated by Scherer's equation was 31.50 nm. The maximum electrical conductivity was found to be 12.567 S/cm and 5.846 S/cm in hydrogen and air atmosphere, respectively at 600 degrees C. The activation energy of the CMZO material was also calculated from the DC conductivity data using Arrhenius plots and it was found to be 0.060 and 0.075 eV in hydrogen and air atmosphere, respectively. The CMZO electrode-based fuel cell was tested using carbonated samarium doped ceria composite (NSDC) electrolyte. The three layers 13 mm in diameter and 1 mm thickness of the symmetric fuel cell were fabricated by dry pressing. The maximum power density of 728.86 mW/cm(2) was measured at 550 degrees C.
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| 2. |
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| 3. |
- Sarfraz, Amina, et al.
(författare)
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Catalytic Effect of Silicon Carbide on the Composite Anode of Fuel Cells
- 2021
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Ingår i: ACS Applied Energy Materials. - : AMER CHEMICAL SOC. - 2574-0962. ; 4:7, s. 6436-6444
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Tidskriftsartikel (refereegranskat)abstract
- High efficiency, fuel flexibility, and sustainable energy conversion make fuel cells attractive compared to conventional energy systems. The direct ethanol fuel cells have attracted much attention because of the direct utilization of ethanol fuel. Anode materials are required to enhance the catalytic activity of the liquid fuel, which oxidize the fuel at lower operating temperature. Therefore, the catalytic effect using silicon carbide has been investigated in the LiNiO2-delta anode. The material has been characterized, and it is found that SiC shows a cubic structure and LiNiO2-delta exhibits a hexagonal structure, while the LiNiO2-delta-SiC composite exhibits a mixed cubic and hexagonal phase. Scanning electron microscopy depicts that the material is porous. The Fourier transform infrared spectroscopy analysis shows the presence of Si-O-Si, Si-C, C=O, and Si-OH bonding. The LiNiO2-delta-SiC composite (1:0.3) exhibited a maximum electrical conductivity of 1.34 S cm(-1) at 650 degrees C with an electrical band gap of 0.84 eV. The fabricated cell with the LiNiO2-delta-SiC anode exhibits a power density of 0.20 W cm(-2) at 650 degrees C with liquid ethanol fuel. The results show that there is a promising catalytic activity of SiC in the fuel cell anode.
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| 4. |
- Abbas, Ghazanfar, et al.
(författare)
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Electrochemical study of nanostructured electrode for low-temperature solid oxide fuel cell (LTSOFC)
- 2014
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Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 38:4, s. 518-523
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Tidskriftsartikel (refereegranskat)abstract
- Zn-based nanostructured Ba0.05Cu0.25Fe0.10Zn0.60O (BCFZ) oxide electrode material was synthesized by solid-state reaction for low-temperature solid oxide fuel cell. The cell was fabricated by sandwiching NK-CDC electrolyte between BCFZ electrodes by dry press technique, and its performance was assessed. The maximum power density of 741.87 mW-cm(-2) was achieved at 550 degrees C. The crystal structure and morphology were characterized by X-ray diffractometer (XRD) and SEM. The particle size was calculated to be 25 nm applying Scherer's formula from XRD data. Electronic conductivities were measured with the four-probe DC method under hydrogen and air atmosphere. AC Electrochemical Impedance Spectroscopy of the BCFZ oxide electrode was also measured in hydrogen atmosphere at 450 degrees C.
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| 5. |
- Afroz, Laila, et al.
(författare)
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Nanocomposite Catalyst (1 – x)NiO-xCuO/yGDC for Biogas Fueled Solid Oxide Fuel Cells
- 2023
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 6:21, s. 10918-10928
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Tidskriftsartikel (refereegranskat)abstract
- The composites of Ni–Cu oxides with gadolinium doped ceria (GDC) are emerging as highly proficient anode catalysts, owing to their remarkable performance for solid oxide fuel cells operated with biogas. In this context, the nanocomposite catalysts (1 – x)NiO-xCuO/yGDC (x = 0.2–0.8; y = 1,1.3) are synthesized using a solid-state reaction route. The cubic and monoclinic structures are observed for NiO and CuO phases, respectively, while CeO2 showed cubic fluorite structure. The scanning electron microscopic images revealed a rise in the particle size with an increase in the copper and GDC concentration. The optical band gap values are calculated in the range 2.82–2.33 eV from UV–visible analysis. The Raman spectra confirmed the presence of vibration modes of CeO2 and NiO. The electrical conductivity of the nanocomposite anodes is increased as the concentration of copper and GDC increased and reached at 9.48 S cm–1 for 0.2NiO-0.8CuO/1.3GDC composition at 650 °C. The electrochemical performance of (1 – x)NiO-xCuO/yGDC (x = 0.2–0.8; y = 1,1.3)-based fuel cells is investigated with biogas fuel at 650 °C. Among all of the as-synthesized anodes, the fuel cell with composition 0.2NiO-0.8CuO/1.3GDC showed the best performance, such as an open circuit voltage of 0.84 V and peak power density of 72 mW cm–2. However, from these findings, it can be inferred that among all other compositions, the 0.2NiO-0.8CuO/1.3GDC anode is a superior combination for the high electrochemical performance of solid oxide fuel cells fueled with biogas.
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| 6. |
- Ahmad, Ashfaq, et al.
(författare)
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Design, Fabrication, and Measurements of Extended L-Shaped Multiband Antenna for Wireless Applications
- 2018
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Ingår i: Applied Computational Electromagnetics Society Journal. - : Applied Computational Electromagnetics Society (ACES). - 1054-4887. ; 33:4, s. 388-393
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Tidskriftsartikel (refereegranskat)abstract
- This article expounds a multi-band compact shaped antenna, which is based on CPW ground plane. FR-4 with a thickness of 1.6 mm is used as a substrate for the proposed antenna. The proposed antenna is capable of operating at 1.56 GHz for (Global Positioning System), 2.45 GHz (Wireless Local Area Network) and 4.49 GHz (Aeronautical Mobile Telemetry (AMT) fixed services). The efficiency at 1.56, 2.45, and 4.49 GHz is 79.7, 76.9 and 76.7%, respectively. The VSWR of the presented antenna is less than 1.5 at all the desired resonance modes, which confirms its good impedance matching. The performance of the proposed antenna is evaluated in terms of VSWR, return loss, radiation pattern and efficiency. CST (R) MWS (R) software is used for simulations. In order to validate the simulation results, a prototype of the designed antenna is fabricated and a good agreement is found between the simulated and measured results.
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| 7. |
- Ahmad, Ashfaq, et al.
(författare)
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Flexible and Compact Spiral-Shaped Frequency Reconfigurable Antenna for Wireless Applications
- 2020
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Ingår i: IETE Journal of Research. - : TAYLOR & FRANCIS LTD. - 0377-2063 .- 0974-780X. ; 66:1, s. 22-29
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Tidskriftsartikel (refereegranskat)abstract
- A flexible, spiral-shaped frequency reconfigurable antenna with a compact size (20 x 24 mm(2)) is presented. The proposed antenna has a low-profile planar structure and is able to operate at five different frequency bands, i.e., 4.19-4.48, 5.98-6.4, 3.42-4.0, 5.4-5.68, and 6.8-7.0 GHz. The multiband operation enables the antenna to cover aeronautical radio navigation, fixed satellite communication, WLAN, and WiMAX standards. A radiating element is backed by Rogers (R) 5880 substrate with a thickness of 0.508 mm and dielectric constant of 2.2. The spiral shape is achieved by introducing different strips. Frequency reconfiguration is achieved by the incorporation of a lumped element in a strip, so that the antenna can switch between different resonances. To validate the performance of the antenna, the prototype of the design was fabricated and tested. Good acquiescent is seen between simulated and measured results. The proposed antenna operates efficiently with appreciable return loss, directivity, bandwidth, and peak gain.
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| 8. |
- Ahmad, Muhammad Ashfaq, et al.
(författare)
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Structural and electrical characterisation of nanostructure electrodes for SOFCs
- 2014
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 39:30, s. 17487-17491
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports the effects of sintering temperature on structure, particle size and conductivity of electrodes (Sn0.2Zn0.8Fe0.2O & Sn0.8Zn0.2Fe0.2O). The electrode material was prepared by the chemical method combining a solid state reaction. Structural analyses were performed using X-ray diffraction and scanning electron microscopy. The particle size of the material obtained using Scherrer's formula was 50-60 nm and the nanostructure's surface was studied using electrochemical characterisations tools. Electrical conductivity was determined using the 4-probe DC method, which was compared with the 4-probe AC method. These results suggest a promising substitute for the conventional electrodes of solid oxide fuel cells (SOFCs). It is known that a sintering temperature above 1000 degrees C causes an increase in density and a reduction of porosity. Therefore, we optimised the sintering temperature at 1000 degrees C and obtained electrical conductivity of about 5 S Thus, this electrode could play a vital role in the development of high performance SOFCs at intermediate temperatures.
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| 9. |
- Ahmad, Shafqat, et al.
(författare)
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Gene × physical activity interactions in obesity: combined analysis of 111,421 individuals of European ancestry. : combined analysis of 111,421 individuals of European ancestry
- 2013
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7404. ; 9:7, s. 1003607-1003607
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Tidskriftsartikel (refereegranskat)abstract
- Numerous obesity loci have been identified using genome-wide association studies. A UK study indicated that physical activity may attenuate the cumulative effect of 12 of these loci, but replication studies are lacking. Therefore, we tested whether the aggregate effect of these loci is diminished in adults of European ancestry reporting high levels of physical activity. Twelve obesity-susceptibility loci were genotyped or imputed in 111,421 participants. A genetic risk score (GRS) was calculated by summing the BMI-associated alleles of each genetic variant. Physical activity was assessed using self-administered questionnaires. Multiplicative interactions between the GRS and physical activity on BMI were tested in linear and logistic regression models in each cohort, with adjustment for age, age(2), sex, study center (for multicenter studies), and the marginal terms for physical activity and the GRS. These results were combined using meta-analysis weighted by cohort sample size. The meta-analysis yielded a statistically significant GRS × physical activity interaction effect estimate (Pinteraction = 0.015). However, a statistically significant interaction effect was only apparent in North American cohorts (n = 39,810, Pinteraction = 0.014 vs. n = 71,611, Pinteraction = 0.275 for Europeans). In secondary analyses, both the FTO rs1121980 (Pinteraction = 0.003) and the SEC16B rs10913469 (Pinteraction = 0.025) variants showed evidence of SNP × physical activity interactions. This meta-analysis of 111,421 individuals provides further support for an interaction between physical activity and a GRS in obesity disposition, although these findings hinge on the inclusion of cohorts from North America, indicating that these results are either population-specific or non-causal.
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| 10. |
- Ahmad, Shafqat, et al.
(författare)
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Gene x physical activity interactions in obesity : combined analysis of 111,421 individuals of European ancestry
- 2013
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Ingår i: PLOS Genetics. - : Public Library of Science. - 1553-7390 .- 1553-7404. ; 9:7, s. e1003607-
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Tidskriftsartikel (refereegranskat)abstract
- Numerous obesity loci have been identified using genome-wide association studies. A UK study indicated that physical activity may attenuate the cumulative effect of 12 of these loci, but replication studies are lacking. Therefore, we tested whether the aggregate effect of these loci is diminished in adults of European ancestry reporting high levels of physical activity. Twelve obesity-susceptibility loci were genotyped or imputed in 111,421 participants. A genetic risk score (GRS) was calculated by summing the BMI-associated alleles of each genetic variant. Physical activity was assessed using self-administered questionnaires. Multiplicative interactions between the GRS and physical activity on BMI were tested in linear and logistic regression models in each cohort, with adjustment for age, age(2), sex, study center (for multicenter studies), and the marginal terms for physical activity and the GRS. These results were combined using meta-analysis weighted by cohort sample size. The meta-analysis yielded a statistically significant GRS x physical activity interaction effect estimate (P-interaction = 0.015). However, a statistically significant interaction effect was only apparent in North American cohorts (n = 39,810, P-interaction = 0.014 vs. n = 71,611, P-interaction = 0.275 for Europeans). In secondary analyses, both the FTO rs1121980 (P-interaction = 0.003) and the SEC16B rs10913469 (P-interaction = 0.025) variants showed evidence of SNP x physical activity interactions. This meta-analysis of 111,421 individuals provides further support for an interaction between physical activity and a GRS in obesity disposition, although these findings hinge on the inclusion of cohorts from North America, indicating that these results are either population-specific or non-causal.
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| 11. |
- Ali, Amjad, et al.
(författare)
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A potential electrolyte (Ce1-x CaxO2-delta) for fuel cells:Theoretical andexperimental study
- 2018
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Ingår i: Ceramics International. - : ELSEVIER SCI LTD. - 0272-8842 .- 1873-3956. ; 44:11, s. 12676-12683
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Tidskriftsartikel (refereegranskat)abstract
- First-principles calculations are performed using density function theory to explore the effects of dopant Ca in ceria (Ce1-x CaxO2-delta). The impact of oxygen vacancy on band gap and density of states is examined in doped ceria using generalized gradient approximations. Vacancy association and vacancy formation energies of the doped ceria are calculated to reveal the effect of dopant on ion conduction. The experimental study of the sample Ce0.875Ca0.125O2-delta) was performed to compare with the theoretical results. The obtained results from theoretical calculation and experimental techniques show that oxygen vacancy increases the volume, lattice constant (5.47315 angstrom) but decrease the band gap (1.72 eV) and bulk modulus. The dopant radius (1.173 angstrom) and lattice constant (5.4718 angstrom) are also calculated by equations which is close to the DFT lattice parameter. The result shows that oxygen vacancy shifts the density of states to lower energy region. Band gap is decreased due to shifting of valence states to conduction band. Vacancy formation shows a significance increase in density of states near the Fermi level. Density of states at Fermi level is proportional to the conductivity, so an increase in density of states near the Fermi level increases the conductivity. The experimental measured ionic conductivity is found to 0.095 S cm(-1) at 600 degrees C. The microstructural studies is also reported in this work.
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| 12. |
- Ali Ahmad, Syed Ossama, et al.
(författare)
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Application of two-dimensional materials in perovskite solar cells: recent progress, challenges, and prospective solutions
- 2021
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Ingår i: Journal of Materials Chemistry C. - : ROYAL SOC CHEMISTRY. - 2050-7526 .- 2050-7534. ; 9:40, s. 14065-14092
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Forskningsöversikt (refereegranskat)abstract
- Perovskite solar cells (per-SCs) with high performance and cost-effective solution processing have been the center of interest for researchers in the past decade. Power conversion efficiencies (PCEs) have been gradually improved up to 25.2% with relatively improved stability, which is an unparalleled progress in all generations of solar cell (SC) technology. However, there are still some prevailing challenges regarding the stability and upscaling of these promising devices. Recently, 2D layered materials (LMs) have been extensively explored to overcome the prevailing challenges of poor stability (under moisture, light soaking and high temperature), halide segregation, hysteresis, involvement of toxic materials (i.e., lead), and upscaling of devices. A critical review addressing the recent developments in the use of 2D materials, especially transition metal dichalcogenides (TMDCs), is hence necessary. The development of novel synthesis and deposition techniques including liquid-metal synthesis and ultrasonic assisted spray pyrolysis has offered more efficient fabrication of 2D-LMs with controlled thickness and morphology. Effective functionalization approaches to increase the dispersability of 2D-LMs in non-polar solvents has boosted their potential application in solar cell technology as well. Moreover, compositing 2D TMDCs with suitable organic/inorganic compounds has enabled superior charge kinetics in all functional parts of per-SCs. In addition, newly developed materials such as graphyne and graphdyine along with 2D metal organic frameworks (MOFs) and covalent organic frameworks (COFs) have been employed in per-SCs to achieve PCEs up to 20%. This review summarizes the recent progress and challenges in the application of 2D-LMs in per-SCs and outlines the future pathways to further extend the PCE of per-SCs beyond 25%. This review particularly focuses on 2D-LMs as electrode materials and additives, the underlying charge (electron-hole) transport phenomenon in the functional layers, and their chemical and structural stability.
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| 13. |
- Anwar, Sahreen, et al.
(författare)
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Intrarater reliability of cervical range of motion device in measuring cervical active range of motion in patients with chronic neck pain and respiratory dysfunction
- 2022
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Ingår i: Anaesthesia, Pain and Intensive Care. - : Faculty of Anaesthesia, Pain and Intensive Care, AFMS. - 1607-8322 .- 2220-5799. ; 26:4, s. 503-509
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Tidskriftsartikel (refereegranskat)abstract
- Background: Assessment of cervical active range of motion (CAROM) in three planes was one of the primary outcome measures used by the clinicians.Methodology: We enrolled 30 patients (14 males and 16 females) with chronic neck pain and respiratory dysfunction fulfilling inclusion criteria. Two trials of CAROM measurement for flexion, extension, left and right lateral flexion and left and right rotation were performed, with a gap of one week to measure test retest reliability of CROM device. Intraclass correlation coefficient (ICC), standard errors of measurement (SEM) and minimal detectable change (MDC) were calculated to test the intrarater reliability.Results: Intrarater reliability of repeated measurements of CAROM using the CROM device was found to be good. The ICC values ranged between 0.88-0.97 for flexion, 0.93-0.98 for extension, 0.92-0.98 for right lateral flexion,0.93-0.98 for left lateral flexion. For right rotation it was 0.88-0.97, for left lateral rotation it was 0.95-0.99. The standard error of measurement for these movements ranged from 1.5° to 2.9°. Minimal detectable change ranged from 3.5°for extension to 6.8°for left lateral flexion.Conclusion: Cervical range of motion device is a reliable tool for measuring cervical active range of motion in patients simultaneously suffering from chronic neck pain and respiratory dysfunction.
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| 14. |
- Asim, Muhammad, et al.
(författare)
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Techno-economic assessment of energy and environmental impact of waste-to-energy electricity generation
- 2023
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Ingår i: Energy Reports. - : Elsevier. - 2352-4847. ; 9:Suppl 1, s. 1087-1097
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Tidskriftsartikel (refereegranskat)abstract
- This study explored cumulative 127.5MW waste to energy (WtE) potential in five populous cities of Pakistan based on local waste characterization profiles and global standards. The 50MW WtE plant in Lahore using National electricity regulator codes and practices resulted in an attractive Levelized cost of electricity (LCOE) of US¢ 7.86/kWh over 25 years with a $151.5 million investment cost. The net savings to Lahore Waste Management Company can be $103.4 and $137.7 million respectively with and without tipping fees on account of waste disposal cost, bricks revenue using bottom ash, and waste fee. The project developers can get net savings of $16.9 and $51.5 million respectively with and without tipping fees other than LCOE. Furthermore, the greenhouse gas emissions of 216.6 million tons of CO2eq can be saved throughout plant life against 279 GWh/year energy generation, in terms of grid emission factor and current methane release into the atmosphere from the dumping site.
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| 15. |
- Batool, Sana, et al.
(författare)
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Effects of visual scanning exercises in addition to task specific approach on balance and activities of daily livings in post stroke patients with eye movement disorders : a randomized controlled trial
- 2022
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Ingår i: BMC Neurology. - : BioMed Central. - 1471-2377. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Impaired vision is one of the commonest and most disabling consequence following stroke. Among all visual impairments, eye movement disorders are found in 70% of stroke patients which include nystagmus, strabismus, gaze palsies, disconjugate eye movements and cranial nerve palsies. They have a wide ranging impact on balance and activities of daily livings by creating difficulties in maintaining normal alignment and appropriate movement of eyes. The purpose of this study was to examine the effects of visual scanning exercises in addition to task specific approach on balance and activities of daily livings in post stroke patients with eye movement disorders.METHODS: This study is a randomized controlled trial and was conducted in the University of Lahore Teaching Hospital from May 2019 to October 2020. A sample of 64 patients was recruited and randomly allocated into experimental and control group. 32 patients in experimental group were treated with visual scanning exercises along with task specific approach and 32 patients in control group were treated with task specific approach alone. Pre and post assessment of balance and activities of daily livings was assessed on BERG BALANCE SCALE and BARTHEL INDEX SCALE at baseline and at 4th week.RESULTS: Intra-group analysis of BERG BALANCE SCALE in experimental group showed statistically significant result (p < 0.05) in all items except in items 4, 13 and 14 respectively. Intra-group analysis of BERG BALANCE SCALE in control group showed statistically significant result (p < 0.05) in items 3, 5, 8 and 12 respectively, whereas remaining all items showed statistically insignificant result. Intra-group analysis of BARTHEL INDEX SCALE in experimental group showed statistically significant result in all items (p < 0.05) except in items 9 and 10 respectively. Intra-group analysis of BARTHEL INDEX in control group showed statistically significant result (p < 0.05) in items 1, 3, 4 and 8 respectively whereas remaining all items showed statistically insignificant result. Inter-group analysis showed statistically significant result in total scores of BERG BALANCE SCALE (p = 0.000) and BARTHEL INEX SCALE (p = 0.033).CONCLUSION: Visual scanning exercises along with task specific approach were found to be more effective in comparison to task specific approach alone.TRIAL REGISTRATION: Trial registration number: [IRCT20190717044237N1], trial registration date: 10/11/2019.
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| 16. |
- Batool, Sana, et al.
(författare)
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Intrarater and interrater reliability of the dynamic gait index in post stroke patients with eye movement disorders
- 2023
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Ingår i: Journal of Bodywork & Movement Therapies. - : Elsevier. - 1360-8592 .- 1532-9283. ; 35, s. 38-42
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Tidskriftsartikel (refereegranskat)abstract
- Background: The Dynamic Gait Index (DGI) is a useful tool that has been evaluated for its reliability in patients with vestibular disorders, elderly people and, in chronic stroke population. Present study was aimed to evaluate the intrarater and interrater reliability of the DGI to measure dynamic balance and gait performance in stroke patients with eye movement disorders. Methods: A sample of 30 stroke patients suffering from eye movement disorders were recruited. Two Physical therapists assessed the intrarater and interrater reliability of the DGI in two testing sessions three days apart. In the later session, two raters assessed the patients' performance simultaneously on the DGI. The reliability was calculated using the intra-class correlation coefficient (ICC2, 1). Standard error of measurement (SEM) and minimal detectable change (MDC95) at 95% confidence interval were also calculated. A significance level was set at p-value <0.05. Results: The (ICC2, 1) for intrarater and interrater reliability of total DGI scores was 0.86 and 0.91 respectively. While (ICC2, 1) for intrarater and interrater reliability of individual items ranged from 0.73 to 0.91 to 0.73–0.93, respectively. The (SEM) and (MDC95) for intrarater reliability of total DGI scores were 0.76 and 2.10, respectively. Corresponding values for interrater reliability were 0.62 and 1.71, respectively. Conclusions: The DGI is a reliable tool for evaluating the dynamic balance and gait performance in stroke patients with eye movement disorders. This tool showed good to excellent intrarater and interrater reliability of total DGI scores and moderate to good intrarater and interrater reliability of individual items of the DGI.
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| 17. |
- Hassan, Mohsan, et al.
(författare)
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The Impact of Different Arrangements of Molecular Chains in Terms of Low and High Shear Rate’s Viscosities on Heat and Mass Flow of Nonnewtonian Shear thinning Fluids
- 2022
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Ingår i: Combinatorial chemistry & high throughput screening. - : Bentham Science Publishers. - 1386-2073 .- 1875-5402. ; 25:7, s. 1115-1126
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Tidskriftsartikel (refereegranskat)abstract
- Background: Non-newtonian fluids, especially shear thinning fluids, have several applications in the polymer industry, food industry, and even everyday life. The viscosity of shear thinning fluids is decreased by two or three orders of magnitude due to the alignment of the molecules in order when the shear rate is increased, and it cannot be ignored in the case of polymer processing and lubrication problems.Objective: So, the effects of viscosities at the low and high shear rates on the heat and mass boundary layer flow of shear thinning fluid over moving belts are investigated in this study. For this purpose the generalized Carreau model of viscosity relate to shear rate is used in the momentum equation. The Carreau model contains the five parameters: low shear rate viscosity, high shear rate viscosity, viscosity curvature, consistency index, and flow behavior index. For the heat flow, the expression of the thermal conductivity model similar to the viscosity equation due to the non-Newtonian nature of the fluid is used in the energy equation.Methods: On the mathematical model of the problem, boundary layer approximations are applied and then simplified by applying the similarity transformations to get the solution. The solution of the simplified equations is obtained by numerical technique RK-shooting method. The results are compared with existing results for limited cases and found good agreement.Results: The results in the form of velocity and temperature profiles under the impact of all the viscosity’s parameters are obtained and displayed in graphical form. Moreover, the boundary layer parameters such as the thickness of the regions, momentum thickness, and displacement thickness are calculated to understand the structure of the boundary layer flow of fluid.Conclusion: The velocity and temperature of the fluid are decreased and increased respectively by all viscosity’s parameters of the model. So, the results of the boundary layer fluid flow under rheological parameters will not only help engineers to design superior chemical equipment but also help improve the economy and efficiency of the overall process.
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| 18. |
- Hussain, Fida, et al.
(författare)
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A modeling approach for low-temperature SOFC-based micro-combined heat and power systems
- 2019
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Ingår i: International Journal of Modern Physics B. - : WORLD SCIENTIFIC PUBL CO PTE LTD. - 0217-9792. ; 33:4
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Tidskriftsartikel (refereegranskat)abstract
- The world's challenge is to determine a more efficient, economical and environmental-friendly energy source to compete and replace the ongoing conventional energy resources. Solid oxide fuel cells (SOFCs) provide a highly efficient system to use divergent energy resources and have proved to provide the cleanest energy, least energy use, and lowest emissions. A techno-economic study is required to investigate the model design for SOFC-based micro-combined heat and power (m-CHP) systems for applications in terms of educational and commercial buildings. This work models and explores the optimized application of hydrogen gas-fueled SOFC-based m-CHP systems in educational buildings. Two educational departments' loads are presented and model of SOFC-based m-CHP system against the different electric power demands is performed, in order to provide a techno-economic assessment of the technology. For successful development of the technology, results are related to system rightsizing, operating strategies, thermal to electric ratios, and match between end-use, with an aim towards classifying the overall feasibility and essential application requirements.
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| 19. |
- Hussain, Fida, et al.
(författare)
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Comparative electrochemical investigation of zinc based nano-composite anode materials for solid oxide fuel cell
- 2019
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Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 45:1, s. 1077-1083
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Tidskriftsartikel (refereegranskat)abstract
- The structural and electrochemical properties of zinc based nano-composites anode materials with a composition of X0.25Ti0.5Zn0.70 (where X = Cu, Mn, Ag) have been investigated in this present study. The proposed Xo.zsTiousZno.70 oxide materials have been synthesized through sol-gel method. The doping effect of Cu, Mn, and Ag on TiZn oxides were analyzed in terms of electronic conduction and power density in hydrogen atmosphere at comparatively low temperature in the range of 650 degrees C. The crystal structure and surface morphology were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis techniques. The XRD patterns of composites depict that the average crystalline sizes lie in the range of 20-100 nm. Four -probe DC conductivity technique was used to measure the conductivity of the materials and maximum electrical conductivity of Ag0.25Ti0.05Zn0.70 oxide was found to be 7.81 S/cm at 650 degrees C. The band gap and absorption spectra were determined by ultra-violet visible (UV-Vis) and Fourier Transform Infrared spectroscopy (FTIR) techniques respectively. The maximum power density was achieved to be 354 mW/cm(2) at 650 degrees C by Ag0.25Ti0.05Zn0.70 oxide anode with SDC (electrolyte) and BSCF (conventional cathode) materials.
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| 20. |
- 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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| 21. |
- Javaid, Nadeem, et al.
(författare)
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An Enhanced Energy Balanced Data Transmission Protocol for Underwater Acoustic Sensor Networks
- 2016
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Ingår i: Sensors. - : MDPI AG. - 1424-8220. ; 16:4
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents two new energy balanced routing protocols for Underwater Acoustic Sensor Networks (UASNs); Efficient and Balanced Energy consumption Technique (EBET) and Enhanced EBET (EEBET). The first proposed protocol avoids direct transmission over long distance to save sufficient amount of energy consumed in the routing process. The second protocol overcomes the deficiencies in both Balanced Transmission Mechanism (BTM) and EBET techniques. EBET selects relay node on the basis of optimal distance threshold which leads to network lifetime prolongation. The initial energy of each sensor node is divided into energy levels for balanced energy consumption. Selection of high energy level node within transmission range avoids long distance direct data transmission. The EEBET incorporates depth threshold to minimize the number of hops between source node and sink while eradicating backward data transmissions. The EBET technique balances energy consumption within successive ring sectors, while, EEBET balances energy consumption of the entire network. In EEBET, optimum number of energy levels are also calculated to further enhance the network lifetime. Effectiveness of the proposed schemes is validated through simulations where these are compared with two existing routing protocols in terms of network lifetime, transmission loss, and throughput. The simulations are conducted under different network radii and varied number of nodes.
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| 22. |
- Kim, Min, et al.
(författare)
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Primary fatty amides in plasma associated with brain amyloid burden, hippocampal volume, and memory in the European Medical Information Framework for Alzheimer's Disease biomarker discovery cohort
- 2019
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Ingår i: Alzheimer's & Dementia. - : Elsevier. - 1552-5260 .- 1552-5279. ; 15:6, s. 817-827
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: A critical and as-yet unmet need in Alzheimer's disease (AD) is the discovery of peripheral small molecule biomarkers. Given that brain pathology precedes clinical symptom onset, we set out to test whether metabolites in blood associated with pathology as indexed by cerebrospinal fluid (CSF) AD biomarkers.METHODS: This study analyzed 593 plasma samples selected from the European Medical Information Framework for Alzheimer's Disease Multimodal Biomarker Discovery study, of individuals who were cognitively healthy (n = 242), had mild cognitive impairment (n = 236), or had AD-type dementia (n = 115). Logistic regressions were carried out between plasma metabolites (n = 883) and CSF markers, magnetic resonance imaging, cognition, and clinical diagnosis.RESULTS: Eight metabolites were associated with amyloid β and one with t-tau in CSF, these were primary fatty acid amides (PFAMs), lipokines, and amino acids. From these, PFAMs, glutamate, and aspartate also associated with hippocampal volume and memory.DISCUSSION: PFAMs have been found increased and associated with amyloid β burden in CSF and clinical measures.
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| 23. |
- Majeed, Khaliq, et al.
(författare)
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Shuffled Complex Evolution-Based Performance Enhancement and Analysis of Cascade Liquefaction Process for Large-Scale LNG Production
- 2020
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Ingår i: Energies. - : MDPI. - 1996-1073. ; 13:10
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Tidskriftsartikel (refereegranskat)abstract
- Among all large-scale natural gas (NG) liquefaction processes, the mixed fluid cascade (MFC) process is recognized as a best-alternative option for the LNG production, mainly due its competitive performance. However, from a thermodynamic point of view, the MFC process is still far from its potential maximum energy efficiency due to non-optimal execution of design variables. Therefore, the energy efficiency enhancement of the MFC process remains an ongoing issue. The design optimization after fixing the main configuration of the process is one of the most economic, but challenging exercises during the design stages. In this study, shuffled complex evolution (SCE) is studied to find the optimal design of the MFC process corresponding to minimal energy consumption in refrigeration cycles. The MFC process is simulated using Aspen Hysys((R)) v10 and then coupled with the SCE approach, which is coded in MATLAB((R)) 2019a. The refrigerant composition and operating pressures for each cycle of the MFC process were optimized considering the approach temperature inside the LNG heat exchanger as a constraint. The resulting optimal MFC process saved 19.76% overall compression power and reduced the exergy destruction up to 28.76%. The thermodynamic efficiency (figure of merit) of the SCE-optimized process was 25% higher than that of the published base case. Furthermore, the optimization results also imply that there is a trade-off between the thermodynamic performance improvement and the computational cost (no. of iterations). In conclusion, SCE exhibited potential to improve the performance of highly nonlinear and complex processes such as LNG processes.
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| 24. |
- Rafique, Asia, et al.
(författare)
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An efficient carbon resistant composite Ni0.6Zn0.4O2-delta-GDC anode for biogas fuelled solid oxide fuel cell
- 2019
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Ingår i: Journal of Power Sources. - : ELSEVIER. - 0378-7753 .- 1873-2755. ; 438
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the fabrication of Ni0.6Zn0.4-Gd0.2Ce0.8O2-delta (NiZn-GDC) via a two-step wet chemical synthesis technique. This composite was found to be more thermally stable and carbon resistive under the intense reducing environment of biogas. This was confirmed by different characterization techniques. The maximum power density P-max, was achieved at 600 degrees C as 820 mW/cm(2) and 548 mW/cm(2) with hydrogen and biogas, respectively. Different characterization techniques have been performed, such as X-ray diffractometry (XRD), scanning electron microscopy (SEM/EDX), UV visible spectroscopy, and Raman spectroscopy. The XRD pattern by Rietveld refinement showed two-phase structures of the anode composite with an average crystallite size of 25 35 nm before and after reduction with methane. The optical band gap (E-g(opt)) of NiZn-GDC was calculated to be 2.24eV from the Tauc plot using absorbance data. The Nyquist plot was also drawn to study the AC electrochemical impedance spectra (EIS) of the nanocomposite anode from 450 degrees C to 600 degrees C in air. The maximum DC conductivity of 1.37 S/cm was observed at a temperature of 600 degrees C using the four-probe DC technique.
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| 25. |
- Rafique, Asia, et al.
(författare)
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Multioxide phase-based nanocomposite electrolyte (M@SDC where M = Zn2+ / Ba2+/ La2+/Zr-2/Al3+) materials
- 2020
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Ingår i: Ceramics International. - : ELSEVIER SCI LTD. - 0272-8842 .- 1873-3956. ; 46:52, s. 6882-6888
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Tidskriftsartikel (refereegranskat)abstract
- This paper deals with the development of a highly dense and stable electrolyte on the base of nanoionics oxide interface theory. This gives a comparative study of two-phase nanocomposite electrolytes that are developed for low temperature solid oxide fuel cells (LT-SOFCs). These nanocomposites are synthesised with different oxides, which are coated on the doped ceria that showed high oxide ion mobility for LT-SOFCs. These novel two-phase nanocomposite oxide ionic conductors (MCe0.8Sm0.2O2-MO2, where M = Zn2+/Ba2+/La3+/Zr2+/Al3+) were synthesised by a co-precipitation method. The interface study between these two phases was analysed by electrochemical impedance spectroscopy (EIS), while ionic conductivities were measured with DC conductivity (four probe method). The nanocomposite electrolytes exhibited higher conductivities with the increase of concentration of coated oxides but decreased at a certain level. The structural or morphological properties of the nanocomposite electrolytes were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The thermal stability was investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The maximum performance of 590 mW/cm(2) at 550 degrees C was obtained for the Zn@SDC based cell, and the rest of the coated samples Ba@SDC, La@SDC, Zr@SDC and Al@SDC based cells showed values of 550 mW/cm(2), 540 mW/cm(2), 450 mW/cm(2), 340 mW/cm(2), respectively, with hydrogen as a fuel. Therefore, the coated-SDC based nanocomposite materials are a good approach for lowering the operating temperature to achieve the challenges of the solid oxide fuel cells (SOFC). These two-phase nanocomposite electrolytes satisfy the all requirements which one electrolyte should have, like high ionic conduction, thermodynamic stability and negligible electronic conduction.
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