| 1. |
- Ayub, Khurram Shahzad, et al.
(författare)
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Efficient post-plasma catalytic degradation of toluene via series of Co-Cu/TiO2 catalysts
- 2022
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Ingår i: Research on chemical intermediates (Print). - : Springer. - 0922-6168 .- 1568-5675. ; 48:10, s. 4227-4248
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Tidskriftsartikel (refereegranskat)abstract
- Volatile organic compounds (VOCs) represent a very important class of pollutants that causes serious health effects. There is an urgent requirement to establish efficient technologies that can reduce and control VOCs. Non-thermal plasma (NTP) is an emerging technology that can decompose low concentration VOCs. However, the low efficiency and high power cost are major hindrances in its commercialization. In this work, Co-Cu with TiO2 support catalysts are prepared by using the deposition precipitation method and utilized in post-plasma catalysis for the efficient degradation of toluene selected as a model VOC. The synergistic effect of Co-Cu/TiO(2)with different Co/Cu molar ratios along with pure Co/TiO2 and Cu/TiO2 catalysts are studied for their catalytic activity. Results showed that the degradation efficiency of toluene for the control experiments (plasma-alone) increased from 10 to 85% with the increase in input power from 11 to 44 W. In comparison, a significant improvement in the degradation efficiency is achieved with post-plasma catalysis owing to better physicochemical properties such as particle surface area and microstructures of the Co-Cu/TiO(2)catalysts. The Co-50-Cu-50/TiO2 exhibited highest degradation efficiency of toluene, i.e. 55% being 5.5 times higher than control at lowest input power of 11 W while 96% at the highest input power of 44 W, attributed to interaction of Co and Cu species, adsorbed oxygen content, and redox properties by exchange of pairs Co+3/Co+2 and Cu+2/Co+3. In summary, the post-plasma catalysis integrated with Co-50-Cu-50/TiO2 catalyst rendered optimal outcomes in terms of power consumption and degradation of VOCs, envisioning commercial viability. [GRAPHICS] .
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| 2. |
- Asif, Shahzad, et al.
(författare)
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An RNS Based Modular Multiplier with Reduced Complexity
- 2017
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Ingår i: 2017 IEEE NORDIC CIRCUITS AND SYSTEMS CONFERENCE (NORCAS): NORCHIP AND INTERNATIONAL SYMPOSIUM OF SYSTEM-ON-CHIP (SOC). - : IEEE. - 9781538628447
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Konferensbidrag (refereegranskat)abstract
- Modular multiplication (MM) based on the residue number system (RNS) is a widely researched area due to the fast arithmetic operations in the RNS. The major drawback of the RNS based MM architectures is their large area because each arithmetic operation is followed by a modular reduction. In this work, the number of modular reductions is reduced and instead the wordlength of some operations is increased to accommodate the intermediate results. The proposed scheme greatly reduces the number of multipliers and achieves a 55% reduction in the hardware complexity. Moreover the delay of the proposed architecture is also significantly lower than the reference architecture.
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| 3. |
- Asif, Shahzad, et al.
(författare)
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Performance analysis of radix-4 adders
- 2012
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Ingår i: Integration. - : Elsevier. - 0167-9260 .- 1872-7522. ; 45:2, s. 111-120
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Tidskriftsartikel (refereegranskat)abstract
- We present a radix-4 static CMOS full adder circuit that reduces the propagation delay, PDP, and EDP in carry-based adders compared with using a standard radix-2 full adder solution. The improvements are obtained by employing carry look-ahead technique at the transistor level. Spice simulations using 45 nm CMOS technology parameters with a power supply voltage of 1.1 V indicate that the radix-4 circuit is 24% faster than a 2-bit radix-2 ripple carry adder with slightly larger transistor count, whereas the power consumption is almost the same. A second scheme for radix-2 and radix-4 adders that have a reduced number of transistors in the carry path is also investigated. Simulation results also confirm that the radix-4 adder gives better performance as compared to a standard 2-bit CLA. 32-Bit ripple carry, 2-stage carry select, variable size carry select, and carry skip adders are implemented with the different full adders as building blocks. There are POP savings, with one exception, for the 32-bit adders in the range 8-18% and EDP savings in the range 21-53% using radix-4 as compared to radix-2.
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| 4. |
- Haneef, Tahir, et al.
(författare)
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Recent progress in two dimensional Mxenes for photocatalysis : a critical review
- 2023
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Ingår i: 2D Materials. - : Institute of Physics (IOP). - 2053-1583. ; 10:1
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Forskningsöversikt (refereegranskat)abstract
- Transition metal carbides and nitrides, generally known as MXenes have emerged as an alternative to improve photocatalytic performance in renewable energy and environmental remediation applications because of their high surface area, tunable chemistry, and easily adjustable elemental compositions. MXenes have many interlayer groups, surface group operations, and a flexible layer spacing that makes them ideal catalysts. Over 30 different members of the MXenes family have been explored and successfully utilized as catalysts. Particularly, MXenes have achieved success as a photocatalyst for carbon dioxide reduction, nitrogen fixation, hydrogen evolution, and photochemical degradation. The structure of MXenes and the presence of hydrophilic functional groups on the surface results in excellent photocatalytic hydrogen evolution. In addition, MXenes' surface defects provide abundant CO2 adsorption sites. Moreover, their highly efficient catalytic oxidation activity is a result of their excellent two-dimensional nanomaterial structure and high-speed electron transport channels. This article comprehensively discusses the structure, synthesis techniques, photocatalytic applications (i.e. H-2 evolution, N-2 fixation, CO2 reduction, and degradation of pollutants), and recyclability of MXenes. This review also critically evaluates the MXene-based heterostructure and composites photocatalyst synthesis process and their performance for organic pollutant degradation. Finally, a prospect for further research is presented in environmental and energy sciences.
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| 5. |
- Iqbal, Jibran, et al.
(författare)
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A Hydrofluoric Acid-Free Green Synthesis of Magnetic M.Ti2CTx Nanostructures for the Sequestration of Cesium and Strontium Radionuclide
- 2022
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Ingår i: Nanomaterials. - : MDPI. - 2079-4991. ; 12:18
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Tidskriftsartikel (refereegranskat)abstract
- Highlights An environmentally friendly MAX phase etching methodology was established Sodium hydroxide produced magnetic layered M.Ti2CTx nanostructure M.Ti2CTx exhibited exceptional Sr2+ and Cs+ removal capacities of 376 and 142.88 mg/g Highly efficient magnetic nanostructures permitted selective radionuclide removal MAX phases are the parent materials used for the formation of MXenes, and are generally obtained by etching using the highly corrosive acid HF. To develop a more environmentally friendly approach for the synthesis of MXenes, in this work, titanium aluminum carbide MAX phase (Ti2AlC) was fabricated and etched using NaOH. Further, magnetic properties were induced during the etching process in a single-step etching process that led to the formation of a magnetic composite. By carefully controlling etching conditions such as etching agent concentration and time, different structures could be produced (denoted as M.Ti2CTx). Magnetic nanostructures with unique physico-chemical characteristics, including a large number of binding sites, were utilized to adsorb radionuclide Sr2+ and Cs+ cations from different matrices, including deionized, tap, and seawater. The produced adsorbents were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). The synthesized materials were found to be very stable in the aqueous phase, compared with corrosive acid-etched MXenes, acquiring a distinctive structure with oxygen-containing functional moieties. Sr2+ and Cs+ removal efficiencies of M.Ti2CTx were assessed via conventional batch adsorption experiments. M.Ti2CTx-A(III) showed the highest adsorption performance among other M.Ti2CTx phases, with maximum adsorption capacities of 376.05 and 142.88 mg/g for Sr2+ and Cs+, respectively, which are among the highest adsorption capacities reported for comparable adsorbents such as graphene oxide and MXenes. Moreover, in seawater, the removal efficiencies for Sr2+ and Cs+ were greater than 93% and 31%, respectively. Analysis of the removal mechanism validates the electrostatic interactions between M.Ti2C-A(III) and radionuclides.
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| 6. |
- Rasool, Kashif, et al.
(författare)
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Comprehensive insights into sustainable conversion of agricultural and food waste into microbial protein for animal feed production
- 2023
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Ingår i: Reviews in Environmental Science and Biotechnology. - : Springer. - 1569-1705 .- 1572-9826. ; 22:2, s. 527-562
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Forskningsöversikt (refereegranskat)abstract
- The growing global population and higher living standards instantly demand the transition in the direction of a sustainable food system. A substantial section of means and agricultural lands are presently committed to protein-rich feed production to rear livestock for human consumption. Conversely, accelerated farming activities and the food industry have rendered a drastic increase in waste which impair the economic and environmental sustainability of the ecosystem. This situation emerges the need for developing an integrated technology for waste management and to improve sustainability footprints. Microbial protein (MP) production based on renewable electron and carbon sources has the potential as a substitute protein source. MP production for animal feed use is growing fast and is derived from bacteria, algae, and fungi including yeast. MP produced from all types of microbes is currently commercialized and in use. However, novel methods and processes are also under investigation to make MP production more economical and sustainable. Current research on MP has concentrated on the valorization of waste materials by using high protein content-containing microorganisms, which can then be used in animal feed. Using such kind of integrated approach, the agroindustry waste resources upcycling can contribute towards finding sustainable, cheaper, and environment-friendly protein sources. This review first describes the potential waste feedstock for MP production and summarizes the recent progress in the application of MP-producing microorganisms including fungus, yeast, bacteria, and phototrophic microbes. Bioprocesses, and production technology advances for MP production have been explored and discussed in detail. Finally, the MP application as animal feed, its challenges, and future perspectives in research have been evaluated.
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| 7. |
- Saeed, Muhammad Ahsan, et al.
(författare)
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2D MXene Additive-Induced Treatment Enabling High-Efficiency Indoor Organic Photovoltaics
- 2023
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Ingår i: Advanced Optical Materials. - : Wiley-VCH Verlagsgesellschaft. - 2162-7568 .- 2195-1071. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- The surge of Internet-of-everything applications over the past decade demands the adoption of novel material design and device engineering strategies for the development of state-of-the-art organic photovoltaics (OPVs) in low-light indoor environments. Owing to their excellent optoelectronic properties, two-dimensional MXenes possess outstanding potential in this regard. Herein, an unprecedented indoor power conversion efficiency (PCE) of 33.8% under light-emitting-diode (LED) illumination (1000-lx) is secured by additive-induced treatment of MXene in polymer-donor:non-fullerene-acceptor-based organic photoactive layer. The remarkable indoor performance of MXene OPVs mainly originates from the enhanced absorption, compact molecular packing, and smooth surface morphology with a reduced number of grain boundaries in the photoactive layer, resulting in an improved fill factor and balanced charge transport and extraction characteristics with suppressed recombination, thereby producing an impressive indoor PCE. In addition, the presence of MXene in the photoactive layer facilitates polaron-pair dissociation owing to improved free-charge generation, leading to enhanced photoconductivity. This performance represents the highest PCE among the OPVs measured under indoor illumination. This work highlights the promising prospect of 2D MXene and its composites for indoor light energy harvesting applications.
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| 8. |
- Shahzad, Asif, et al.
(författare)
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Magnetic nanocomposite for lead (II) removal from water
- 2024
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Ingår i: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- A magnetic perovskite-spinel oxide nanocomposite synthesized through a sol-gel self-combustion process is used for the first time as an adsorbent to remove toxic heavy metals (i.e., Pb2+). The synthesized LaFeO3:CoFe2O4 ((LFO)1:(CFO)x) (x = 0.11-0.87) nanocomposites possess good stability, abundant oxygenated active binding sites, and unique structural features, making them suitable for removing divalent Pb2+ ions. Scanning electron microscopy, X-ray diffraction, BET surface area, magnetization measurements, zeta-potential analyses, and X-ray photoelectron spectroscopy were used to analyze the nanocomposites, and their structural changes after Pb2+ ions adsorption. Batch tests confirmed that (LFO)1:(CFO)x efficiently removes Pb2+ from water with a maximum adsorption capacity of 105.96 mg/g. The detailed quantitative study indicates that the interaction of hydroxyl groups with Pb2+ ions occurs through electrostatic interactions and complex formation. We also demonstrate a new ring-magnetic separator system that allows magnetic separation of the toxic ions at a higher speed compared to traditional block magnets. The unique structure, high porosity, large specific surface area, and oxygenated functional groups of (LFO)1:(CFO)x nanocomposites make them promising materials for removal of heavy metal ions and possibly other environmental pollutants. This study provides a new approach to preparing nanocomposites of magnetic spinel ferrites with perovskite oxides for environmental applications.
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| 9. |
- Sherazi, Syed Muhammad Yasser, et al.
(författare)
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Reduction of Substrate Noise in Sub Clock Frequency Range
- 2010
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Ingår i: IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS. - : IEEE. - 1549-8328. ; 57:6, s. 1287-1297
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Tidskriftsartikel (refereegranskat)abstract
- We propose a method of reducing the switching noise in the substrate of an integrated circuit. The main idea is to design the digital circuits to obtain a periodic supply current with the same period as the clock. This property locates the frequency components of the switching noise above the clock frequency. Differential return-to-zero signaling is used to reduce the data-dependency of the current. Circuits are implemented in symmetrical precharged DCVS logic with internally asynchronous D registers. A chip was fabricated in a standard 130-nm CMOS technology holding two versions of a pipelined 16-bit adder. First version employed the proposed method, and second version used conventional static CMOS logic circuits and TSPC registers. The respective device counts are 1190 and 684, and maximal operating frequencies 450 and 375 MHz. Frequency domain measurements were performed at the substrate node with on-chip generated sinusoidal and pseudo-random data at a clock frequency of 300 MHz. The sinusoidal case resulted in the largest frequency components, where an 8.5 dB/Hz decrease in maximal power is measured for the proposed circuitry at a cost of three times larger power consumption.
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| 10. |
- Ullah, Hameed, et al.
(författare)
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Polyoxometalate based ionic liquids reinforced on magnetic nanoparticles: A sustainable solution for microplastics and heavy metal ions elimination from water
- 2024
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Ingår i: Microchemical journal (Print). - : Elsevier. - 0026-265X .- 1095-9149. ; 204
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Tidskriftsartikel (refereegranskat)abstract
- To purify water from contaminents is essential for life on universe. Here, in this manuscript we introduces an innovative approach to overcome the intricate challenge of eliminating heavy metal ions and microplastics from water. We designed a mesoporous composite materials by synergistically integrating polyoxometalates (POMs) based ionic liquids with silica coated magnetic nanoparticles. The synthesis process initiates with the utilization of highly reduced molybdenum aggregates in polyoxometalate-ionic liquids, reinforced onto magnetic nanoparticles (POM–IL–MNPs). Crafted composites, including Q8[Mo64Ni8La6]@SiO2@Fe3O4, Q10[Mo64Ni8La6]@SiO2@Fe3O4, Q8[Mo176/Mo248]@SiO2@Fe3O4, and Q10[Mo176/Mo248]@SiO2@Fe3O4, are meticulously designed by substituting POM counter cations with long-chain alkyl-based quaternary ammonium salts. The ionic liquids and composites exhibit remarkable hydrophobicity and thermal stability due to large anions and long-chain organic counter cations. Comprehensive characterization, including FT–IR, UV–vis spectroscopy, TGA, DSC, CV, rheological study, elemental analysis, and ICP-AES, ensures a thorough investigation. Additional analyses, such as Powder X-ray diffraction (PXRD), SEM, EDX, DLS, N2 adsorption, and VSM, reveal amorphous crystallinity, distinctive surface morphology, and substantial specific surface area. Core shell structure of POM-IL-MNPs was determined by Transmision electron microscope (TEM), ICP-AES analysis demonstrates metal ion removal efficiencies from 87.35% to 99.98%, with DLS confirming 100% efficiency in PVC beads elimination. This research not only advances water decontamination but also provides valuable insights into designing and characterizing novel materials with promising environmental applications.
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