| 1. |
- Ademuyiwa, Adesoji O., et al.
(författare)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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| 2. |
- Qureshi, Tayyab, et al.
(författare)
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Structural and thermal investigation of lignocellulosic biomass conversion for enhancing sustainable imperative in progressive organic refinery paradigm for waste-to-energy applications
- 2024
-
Ingår i: Environmental Research. - : Elsevier. - 0013-9351 .- 1096-0953. ; 246
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Tidskriftsartikel (refereegranskat)abstract
- The depletion of finite fossil fuel reserves and the severe environmental degradation resulting from human activities have compelled the expeditious development and application of sustainable waste to energy technologies. To encapsulate energy and environment in sustainability paradigm, bio waste based energy production is need to be forged in organic bio refinery setup. According to world bioenergy association, biomass can cover 50 % of the primary energy demand of the world. Therefore, the present study focuses on reforming the energy mix for a clean energy generation, where, sample composition of cotton stalk was acidified in dilute (5% wt.) hydrochloric acid (HCL) for analyzing material burnout patterns in biomass conversion systems utilized in organic bio refinery sector. Advanced thermochemical burning technique, which includes pyrolysis and combustion was applied at four different leaching times from 0 to 180 min under nitrogen environment from 0 degrees C to 500 degrees C and air from 500 degrees C to 900 degrees C, respectively. Different analyses including proximate, ultimate, gross calorific value (GCV), thermos-gravimetric, kinetic, XRD, FTIR, SEM-EDS were used for analyzing the degradation of demineralized cotton stalk at different treatment rates. Proximate study demonstrated that cotton stalk leaching for 180 min has efficiently infused HCL, leading in a significant increase in fixed carbon and higher heating value of 20.23 % and 12.48%, respectively, as well as a reduction in carbon footprint of around 54.80%. The findings of proximate was validated by GCV analysis and CHNS analysis as value of carbon and hydrogen has shown increasing behavior with the time delay in demineralization Thermo-gravimetric and derivative thermo-gravimetric data analyses shows an increasing trend of conversion efficiency, with the maximum increase of 98 % reported for sample 3H. TT.DEM. XRD characterization has reported 23 degrees to 25 degrees angle for all the observed peaks. Sample 3H.TT.DEM has shown maximum angle inclination along with matured crystalline peak. The latter observations has been validated by FTIR spectroscopy as sample 3H.TT.DEM has reported maximum O-H group formation. Sample 3H.TT. DEM has reported lowest activation energy of 139.51 kJ*mole-1 and lowest reactivity of 0.000293649%*min 0C, due to moderate and stable reactiveness. In SEM examination, increment in pore size and number of pores within the structural matrix of cotton stalk was observed with the enhancement in acidulation process. Furthermore, in EDS analysis, 3H.TT.DEM has shown most balanced distribution of the elements. In this research, sustainable transformation of biomass is envisioned to improve the waste bio refinery system, significantly contributing to the achievement of Sustainable Development Goals 7, 12 and 13.
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| 3. |
- Usman, Muhammad, et al.
(författare)
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Use of Gasoline, LPG and LPG-HHO Blend in SI Engine : A Comparative Performance for Emission Control and Sustainable Environment
- 2020
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Ingår i: Processes. - : MDPI. - 2227-9717. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- The rising global warming concerns and explosive degradation of the environment requires the mainstream utilization of alternative fuels, such as hydroxy gas (HHO) which presents itself as a viable substitute for extracting the benefits of hydrogen. Therefore, an experimental study of the performance and emission characteristics of alternative fuels in contrast to conventional gasoline was undertaken. For experimentation, a spark ignition engine was run on a multitude of fuels comprising of gasoline, Liquefied petroleum gas (LPG) and hybrid blend of HHO with LPG. The engine was operated at 60% open throttle with engine speed ranging from 1600 rpm to 3400 rpm. Simultaneously, the corresponding performance parameters including brake specific fuel consumption, brake power and brake thermal efficiency were investigated. Emission levels of CO, CO2, HC and NOx were quantified in the specified speed range. To check the suitability of the acquired experimental data, it was subjected to a Weibull distribution fit. Enhanced performance efficiency and reduced emissions were observed with the combustion of the hybrid mixture of LPG with HHO in comparison to LPG: on average, brake power increased by 7% while the brake specific fuel consumption reduced by 15%. On the other hand, emissions relative to LPG decreased by 21%, 9% and 21.8% in cases of CO, CO2, and unburned hydrocarbons respectively. Incorporating alternative fuels would not only imply reduced dependency on conventional fuels but would also contribute to their sustainability for future generations. Simultaneously, the decrease in harmful environmental pollutants would help to mitigate and combat the threats of climate change.
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| 4. |
- Farooq, Muhammad, et al.
(författare)
-
Thermodynamic Performance Analysis of Hydrofluoroolefins (HFO) Refrigerants in Commercial Air-Conditioning Systems for Sustainable Environment
- 2020
-
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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| 5. |
- Mubeen, Iqra, et al.
(författare)
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Formulation of Modified-Release Bilayer Tablets of Atorvastatin and Ezetimibe : An In-Vitro and In-Vivo Analysis
- 2022
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 14:18
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this work was to formulate co-loaded bilayer tablets containing ezetimibe (EZB) and atorvastatin (ATC). ATC loaded in the immediate-release (IR) layer is an HMG CoA reductase inhibitor, while EZB, added in the sustained-release (SR) layer, is a lipid-lowering agent. This study was conducted to evaluate the effects of polymer on the formulation and characterization of bilayer tablets, as well as the therapeutic impact of the concurrent use of both drugs having a sequential release pattern. To obtain the optimized results, four different formulations with variable compositions were developed and evaluated for different parameters. The drug release studies were carried out using a type II dissolution apparatus, using phosphate buffer solution (PBS) of 1.2 pH for IR of EZB for an initial 2 h, followed by 24 h studies for ATC in PBS 6.8 pH. The IR layer showed rapid drug release (96%) in 2 h, while 80% of the ATC was released in 24 h from the SR layer. Locally obtained, 6-week-old female albino rats were selected for in vivo studies. Both preventive and curative models were applied to check the effects of the drug combination on the lipid profile, atherosclerosis and physiology of different organs. Studies have shown that the administration of both drugs with different release patterns has a better therapeutic effect (p < 0.05), both in preventing and in curing hyperlipidemia. Conclusively, through the sequential release of ATC and EZB, a better therapeutic response could be obtained.
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| 6. |
- Naqvi, Salman Raza, et al.
(författare)
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Potential of biomass for bioenergy in Pakistan based on present case and future perspectives
- 2018
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 81:1, s. 1247-1258
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Forskningsöversikt (refereegranskat)abstract
- Future energy security and environmental issues are major driving forces for increased biomass utilization globally and especially in developing countries like Pakistan. For efficient utilization of indigenous biomass resources in the future energy mix, it is important to gain knowledge of current energy system in various sectors. Some of the technologies and initiatives are under development to achieve transition from non-renewable resources to renewable resources, and reducing fossil fuel dependency and greenhouse gas emissions. Recently, number of proposals has been presented for the development of sustainable biofuels production methods for promise for accelerating a shift away from an unsustainable approach to possible sustainable production practices or a sustainable social, economic and environment. This article presents an extensive literature review of the biomass-based renewable energy potential in Pakistan based on current energy scenario and future perspectives. It also highlights the availability of the indigenous and local biomass resources and potential biomass conversion technologies to convert such resources to bioenergy. The drivers for utilization of indigenous biomass resources in future energy mix and challenges regarding awareness among stakeholders and R & D to fill knowledge gaps are economically restraints. The article concludes with suggestions on future directions and policies for effective implementation of biomass based renewable energy production.
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| 7. |
- Shakoor, Awais, et al.
(författare)
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A global meta-analysis of greenhouse gases emission and crop yield under no-tillage as compared to conventional tillage
- 2020
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697.
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Tidskriftsartikel (refereegranskat)abstract
- No-tillage (NT) practice is extensively adopted with aims to improve soil physical conditions, carbon (C) sequestration and to alleviate greenhouse gases (GHGs) emissions without compromising crop yield. However, the influences of NT on GHGs emissions and crop yields remains inconsistent. A global meta-analysis was performed by using fifty peer-reviewed publications to assess the effectiveness of soil physicochemical properties, nitrogen (N) fertilization, type and duration of crop, water management and climatic zones on GHGs emissions and crop yields under NT compared to conventional tillage (CT) practices. The outcome reveals that compared to CT, NT increased CO2, N2O, and CH4 emissions by 7.1, 12.0, and 20.8%, respectively. In contrast, NT caused up to 7.6% decline in global warming potential as compared to CT. However, absence of difference in crop yield was observed both under NT and CT practices. Increasing N fertilization rates under NT improved crop yield and GHGs emission up to 23 and 58%, respectively, compared to CT. Further, NT practices caused an increase of 16.1% CO2 and 14.7% N2O emission in the rainfed areas and up to 54.0% CH4 emission under irrigated areas as compared to CT practices. This meta-analysis study provides a scientific basis for evaluating the effects of NT on GHGs emissions and crop yields, and also provides basic information to mitigate the GHGs emissions that are associated with NT practice.
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| 8. |
- 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
-
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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| 9. |
- Arslan, Muhammad, et al.
(författare)
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Impact of Varying Load Conditions and Cooling Energy Comparison of a Double-Inlet Pulse Tube Refrigerator
- 2020
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Ingår i: Processes. - : MDPI. - 2227-9717. ; 8:3
-
Tidskriftsartikel (refereegranskat)abstract
- Modeling and optimization of a double-inlet pulse tube refrigerator (DIPTR) is very difficult due to its geometry and nature. The objective of this paper was to optimize-DIPTR through experiments with the cold heat exchanger (CHX) along the comparison of cooling load with experimental data using different boundary conditions. To predict its performance, a detailed two-dimensional DIPTR model was developed. A double-drop pulse pipe cooler was used for solving continuity, dynamic and power calculations. External conditions for applicable boundaries include sinusoidal pressure from an end of the tube from a user-defined function and constant temperature or limitations of thermal flux within the outer walls of exchanger walls under colder conditions. The results of the system's cooling behavior were reported, along with the connection between the mass flow rates, heat distribution along pulse tube and cold-end pressure, the cooler load's wall temp profile and cooler loads with varied boundary conditions i.e. opening of 20% double-inlet and 40-60% orifice valves, respectively. Different loading conditions of 1 and 5W were applied on the CHX. At 150 K temperature of the cold-end heat exchanger, a maximum load of 3.7 W was achieved. The results also reveal a strong correlation between computational fluid dynamics modeling results and experimental results of the DIPTR.
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| 10. |
- Ashraf, Waqar Muhammad, et al.
(författare)
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Artificial intelligence based operational strategy development and implementation for vibration reduction of a supercritical steam turbine shaft bearing
- 2022
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Ingår i: Alexandria Engineering Journal. - 1110-0168 .- 2090-2670. ; 61:3, s. 1864-1880
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Tidskriftsartikel (refereegranskat)abstract
- The vibrations of bearings holding the high-speed shaft of a steam turbine are critically controlled for the safe and reliable power generation at the power plants. In this paper, two artificial intelligence (AI) process models, i.e., artificial neural network (ANN) and support vector machine (SVM) based relative vibration modeling of a steam turbine shaft bearing of a 660 MW supercritical steam turbine system is presented. After extensive data processing and machine learning based visualization tests performed on the raw operational data, ANN and SVM models are trained, validated and compared by external validation tests. ANN has outperformed SVM in terms of better prediction capability and is, therefore, deployed for simulating the constructed operating scenarios. ANN process model is tested for the complete load range of power plant, i.e., from 353 MW to 662 MW and 4.07% reduction in the relative vibration of the bearing is predicted by the network. Further, various vibration reduction operating strategies are developed and tested on the validated and robust ANN process model. A selected operating strategy which has predicted a promising reduction in the relative vibration of bearing is selected. In order to confirm the effectiveness of the prediction of the ANN process model, the selected operating strategy is implemented on the actual operation of the power plant. The resulting reduction in the relative vibrations of the turbine's bearing, which is less than the alarm limit, are confirmed. This cements the role of ANN process model to be used as an operational excellence tool resulting in vibration reduction of high-speed rotating equipment. (c) 2021 THE AUTHORS. Production and hosting by Elsevier B.V. on behalf of Faculty of Engineering, Alexandria University This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 11. |
- Farooq, Usman, et al.
(författare)
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Synthesis of nZVI@reduced graphene oxide : an efficient catalyst for degradation of 1,1,1-trichloroethane (TCA) in percarbonate system
- 2017
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Ingår i: Research on chemical intermediates (Print). - : SPRINGER. - 0922-6168 .- 1568-5675. ; 43:5, s. 3219-3236
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Tidskriftsartikel (refereegranskat)abstract
- Graphene-oxide-supported nano zero-valent iron (nZVI) composite (nZVI-rGO) was synthesized and tested as an efficient percarbonate activator for degradation of 1,1,1-trichloroethane (TCA). Significant dispersion of nZVI on the surface of reduced graphene oxide (rGO) was observed, with good limitation of nanoparticle agglomeration and aggregation. Good TCA degradation efficiency of 90% was achieved in 2.5 h in presence of 0.8 g/l nZVI-rGO catalyst and 30 mM sodium percarbonate (SPC) oxidant; however, excessive catalyst or oxidant concentration reduced the degradation efficiency. Investigation of reactive oxygen species using radical probe compounds as well as radical scavengers confirmed presence of hydroxyl (OH center dot) and superoxide () radicals that are responsible for the TCA degradation. The morphology and surface characteristics of the heterogeneous catalyst were analyzed by transmission electron microscopy and scanning electron microscopy. Brunauer-Emmett-Teller analysis revealed that the synthesized catalyst had large surface area and small particle size of 299.12 m(2)/g and 20.10 nm, respectively, compared with 5.33 m(2)/g and 1.12 A mu m for bare graphene oxide. X-ray diffraction analysis revealed good dispersion of nZVI on the surface of rGO. Fourier-transform infrared characteristic peaks confirmed strong attachment of Fe onto the rGO surface. Energy-dispersive spectroscopy analysis validated the stoichiometric composition of the prepared Fe/rGO material. In conclusion, use of nZVI-rGO-activated SPC could represent an alternative technique for remediation of TCA-contaminated groundwater.
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| 12. |
- Fatima, Iza, et al.
(författare)
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Individual and synergistic effects of different fertilizers and gibberellin on growth and morphology of chili seedlings
- 2024
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Ingår i: Acta Ecologica Sinica. - 1872-2032. ; 44:2, s. 275-281
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Tidskriftsartikel (refereegranskat)abstract
- Gibberellins (GA3), as well as the basic elements phosphorus (P), nitrogen (N), and potassium (K), are crucial to the growth of chili. This study investigates the effect of different fertilizers and plant growth regulator on the growth and morphology of chili seedlings. Soil application of NPK, urea, SOP, and DAP (2.5 g/L) was applied during sowing, and N in two splits at sowing and after twenty days of sowing while foliar application of GA3 (50 mg/L) was applied after fifteen days of germination. The result of five seedlings' traits plant height (PH), plant girth (PG), plant spread (PS), number of leaves (NOF), and root length (RL) demonstrated a significant difference among growth-related traits in chili seedlings owing to the use of fertilizers, GA3, and their combinations. An optimum level of K and P alone or in combination with GA3 had a significant effect on all traits. PH was particularly influenced by the combination of GA3 with K and P whereas other traits like PG, NOF, PS, and RL are greatly influenced by the application of NPK, urea, SOP, DAP, and their combination with GA3. The study results showed an increase in chili seedlings' growth and morphology in response to various fertilizers and GA3.
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| 13. |
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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. |
- Danish, Muhammad, et al.
(författare)
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An efficient catalytic degradation of trichloroethene in a percarbonate system catalyzed by ultra-fine heterogeneous zeolite supported zero valent iron-nickel bimetallic composite
- 2017
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Ingår i: Applied Catalysis A. - : Elsevier. - 0926-860X .- 1873-3875. ; 531, s. 177-186
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Tidskriftsartikel (refereegranskat)abstract
- Zeolite supported nano iron-nickel bimetallic composite (Z-nZVI-Ni) was prepared using a liquid-phase reduction process. The corresponding surface morphologies and physico-chemical properties of the Z-nZVI-Ni composite were determined using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy dispersive X-ray spectra (EDS), Brunauer Emmett Teller (BET) adsorption, wide angle X-ray diffractometry (WA-XRD), and Fourier transform infrared spectroscopy (FTIR). The results indicated high dispersion of iron and nickel nano particles on the zeolite sheet with an enhanced surface area. Complete destruction of trichloroethene (TCE) and efficient removal of total organic carbon (TOC) were observed by using Z-nZVI-Ni as a heterogeneous catalyst for a Fenton-like oxidation process employing sodium percarbonate (SPC) as an oxidant. The electron spin resonance (ESR) of Z-nZVI-Ni verified the generation and intensity of hydroxyl radicals (OH center dot). The quantification of OH center dot elucidated by using p-chlorobenzoic acid, a probe indicator, confirmed the higher intensity of OH center dot. The transformation products were identified using GC-MS. The slow iron and nickel leaching offered higher stability and better catalytic activity of Z-nZVI-Ni, demonstrating its prospective long term applications in groundwater for TCE degradation. (C) 2016 Elsevier B.V. All rights reserved.
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| 16. |
- Danish, Muhammad, et al.
(författare)
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Characterization of South Asian agricultural residues for potential utilization in future 'energy mix'
- 2015
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Ingår i: Energy Procedia. - : Elsevier. ; 75, s. 2974-2980
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Konferensbidrag (refereegranskat)abstract
- This paper characterizes various locally available agricultural residues in South Asian region to evaluate their potential as feedstock for renewable energy production and contributing toward solving energy crisis and environmental issues. The thermo-chemical characterization has been performed in order to determine if the residues have potential to be used in biomass conversion technologies producing combined heat and power. The characterization methods for comparing different agricultural residues include proximate and ultimate analysis, heating value, ash content, thermo gravimetric analysis (TGA) and structural composition analysis (SCA). Widely available agricultural wastes in South Asian region were selected for the characterization i.e. bagasse, almond shell, corn cob, cotton stalks, wheat straw, sawdust, corn leaf, rice husk, rice straw, and corn straw. The analysis showed that the corn cob had the highest moisture content that will result in low energy efficiency of the thermal conversion technology due to energy requirement for drying. Whereas almond shell had the lowest moisture content. Ash and volatile contents were found to be highest in rice straw and almond shell respectively. The thermo gravimetric analysis showed that most of the agricultural residues can be easily decomposed and represent potential feedstock for biomass flexible combined heat and power systems through pyrolysis or gasification.
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| 17. |
- Danish, Muhammad, et al.
(författare)
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Effect of solution matrix and pH in Z-nZVI-catalyzed percarbonate system on the generation of reactive oxygen species and degradation of 1,1,1-trichloroethane
- 2017
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Ingår i: Water Science and Technology. - London, UK : IWA PUBLISHING. - 1606-9749 .- 1607-0798. ; 17:6, s. 1568-1578
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Tidskriftsartikel (refereegranskat)abstract
- This study primarily focuses on evaluating the effects of solution matrix and pH for the generation of reactive oxygen species (ROSs) in a Z-nZVI-catalyzed sodium percarbonate (SPC) system to degrade 1,1,1-trichloroethane (1,1,1-TCA) in the absence and presence of a reducing agent (RA), i.e. hydroxylamine. Degradation of 1,1,1-TCA was 49.5% and 95% in the absence and presence of RA. Probe tests confirmed the generation of major hydroxyl radicals (OH center dot) and minor superoxide species (O-2(-center dot)), and scavenger tests verified the key role of OH center dot and less of O-2(-center dot) radicals. Degradation of 1,1,1-TCA decreased significantly in the presence of Cl- and HCO3-, while NO3- and SO42- had negligible effects in the absence of RA. Addition of RA significantly enhanced 1,1,1-TCA degradation by generating more OH center dot and O-2(-center dot) radicals in the presence of anions. Degradation of 1,1,1-TCA increased in the acidic range (1-5), while an inhibitive trend from neutral to basic (7-9) was observed. In contrast, a significant increase in 1,1,1-TCA degradation was observed with the addition of RA at all pH values (1-9). In conclusion, the anions and pH significantly influenced the generation and intensity of ROSs and 1,1,1-TCA was effectively degraded in the Z-nZVI-catalyzed SPC system in the presence of RA.
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| 18. |
- Danish, Muhammad, et al.
(författare)
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Efficient transformation of trichloroethylene activated through sodium percarbonate using heterogeneous zeolite supported nano zero valent iron-copper bimetallic composite
- 2017
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Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 308, s. 396-407
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Tidskriftsartikel (refereegranskat)abstract
- Zeolite supported nano zero valent iron copper bimetallic composite (Z-nZVFe-Cu) was synthesized using an ion exchange method. The morphology and physico-chemical properties of the Z-nZVFe-Cu composite were determined using transmission electron microscopy (TEM), scanning electron microscopy (SEM), Brunauer Emmett Teller (BET), energy dispersive X-ray spectra (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometer (XRD). The results showed that iron and copper nano particles were well dispersed on the zeolite sheet. The degradation efficiency of trichloroethylene (TCE) achieved was more than 95% using Z-nZVFe-Cu as a heterogeneous Fenton like catalyst. An efficient removal of total organic carbon (TOC) was promoted as compared to zeolite supported iron nano composite (Z-nZVFe) and unsupported nano iron (nZVFe). Electron spin resonance (ESR) detection confirmed the intensity of hydroxyl radicals (OH.) in the system. While benzoic acid (BA), a probe indicator for the quantification of OH., demonstrated the higher intensity of hydroxyl radicals in Z-nZVFe-Cu as compared to Z-nZVFe and nZVFe. The less iron and copper leaching of from Z-nZVFe-Cu presented its higher stability and better catalytic activity, displaying its potential long term applications for TCE degradation in groundwater. (C) 2016 Elsevier B.V. All rights reserved.
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| 19. |
- Farooq, Muhammad, et al.
(författare)
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Computing Expectiles Using k-Nearest Neighbours Approach
- 2021
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Ingår i: Symmetry. - : MDPI AG. - 2073-8994. ; 13:4
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Tidskriftsartikel (refereegranskat)abstract
- Expectiles have gained considerable attention in recent years due to wide applications in many areas. In this study, the k-nearest neighbours approach, together with the asymmetric least squares loss function, called ex-kNN, is proposed for computing expectiles. Firstly, the effect of various distance measures on ex-kNN in terms of test error and computational time is evaluated. It is found that Canberra, Lorentzian, and Soergel distance measures lead to minimum test error, whereas Euclidean, Canberra, and Average of (L1,L∞) lead to a low computational cost. Secondly, the performance of ex-kNN is compared with existing packages er-boost and ex-svm for computing expectiles that are based on nine real life examples. Depending on the nature of data, the ex-kNN showed two to 10 times better performance than er-boost and comparable performance with ex-svm regarding test error. Computationally, the ex-kNN is found two to five times faster than ex-svm and much faster than er-boost, particularly, in the case of high dimensional data.
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| 20. |
- Fatima, Masoom, et al.
(författare)
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Application of novel bacterial consortium for biodegradation of aromatic amine 2-ABS using response surface methodology
- 2020
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Ingår i: Journal of Microbiological Methods. - : Elsevier BV. - 0167-7012 .- 1872-8359. ; 174
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Tidskriftsartikel (refereegranskat)abstract
- There is a strong need to develop purification methods for textile industrial wastewater containing toxic azo dyes. The reductive cleavage of azo dyes can be made by anaerobic bacteria, but the products of aromatic amines require an aerobic process. In this study a novel bacterial dye degrading consortium (DDC) of five isolated strains identified with 16S rRNA sequence: Proteus mirabilis (KR732288), Bacillus anthracis (KR732289), Enterobacter hormaechei (KR732290), Pseudomonas aeruginosa (KR732293) and Serratia rubidaea (KR732296) were used to aerobically decompose metabolite 2-aminobenxenesulfonic acid (2-ABS), as a model compound. The effect of three variables: temperature (28-42 degrees C), pH (5.0-8.0) and initial concentration of 2-ABS (5-40 ppm) was investigated in terms of degradation and chemical oxygen demand (COD) removal. Central composite design matrixand response surface methodology (RSM) were used for experimental design to evaluate theinteraction of the three process variables. The results show that up to 95% degradation and COD 90% removal are possible at optimal values of 32.4 ppm 2-ABS, pH 6.6 and a temperature of 35.7 degrees C. The theoretical response variables predicted by the developed RSM model was supported the experimental results. The optimized degradation of 2-ABS and COD removal were further confirmed by UV-HPLC analysis.
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| 21. |
- Inayat, Irum, et al.
(författare)
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Security-based Safety Hazard Analysis using FMEA : A DAM Case Study
- 2021
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Ingår i: International Conference on Database and Expert Systems Applications. - Cham : Springer International Publishing.
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Konferensbidrag (refereegranskat)abstract
- Safety and security emerge to be the most significant features of a Cyber-Physical System (CPS). Safety and security of a system are interlaced concepts and have mutual impact on each other. In the last decade, there are many cases where security breach resulted in safety hazards. There have been very few studies in the literature that address the integrated safety security risk assessment. Since, the need of the time is to consider both safety and security concurrently not even consequently. To close this gap, we aim to: (i) perform hazard analysis using Failure Mode Effect Analysis (FMEA) of a cyber physical system case i.e., Dam case study, and (ii) perform risk identification, risk analysis and mitigation for the said case. As a result, we extracted the potential failure modes, failure causes, failure effects, and the risk priority number. In addition, we also identified the safety requirements for the modes of the subject.
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| 22. |
- Khan, Farooq-Ahmad, et al.
(författare)
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Ruthenium Nanoparticles Intercalated in Montmorillonite (nano-Ru@MMT) Is Highly Efficient Catalyst for the Selective Hydrogenation of 2-Furaldehyde in Benign Aqueous Medium
- 2021
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Ingår i: Catalysts. - : MDPI AG. - 2073-4344. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Chemoselective hydrogenation of 2-furaldehyde to furfuryl alcohol using green solvents is an important research area to get eco-friendly fuels and fine chemicals. Herein, we report ruthenium nanoparticles (similar to 1.8 nm) intercalated in montmorillonite as an efficient catalytic system, which can selectively hydrogenate 2-furaldehyde in a benign aqueous medium. The complete conversion was observed at 40 degrees C with 1 MPa H-2, the selectivity of furfuryl alcohol being >99%, and turnover number 1165. After a catalytic run, the montmorillonite-supported ruthenium nanoparticles can be recycled and reused without losing their activity and selectivity.
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| 23. |
- Khan, Muhammad Farooq, et al.
(författare)
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High mobility ReSe2 field effect transistors : Schottky-barrier-height-dependent photoresponsivity and broadband light detection with Co decoration
- 2020
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Ingår i: 2D Materials. - : IOP Publishing. - 2053-1583. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- 2D transition metal dichalcogenides are promising in various electronics and optoelectronics applications and have gained popularity owing to their carrier transport and strong light-matter interactions. To fully realize their potential in field-effect transistors (FETs) and photodetectors, high mobility and high responsivity are imperative. Here, we demonstrate the highest mobility of ∼166 cm2 V-1 s-1 at 200 K for single-layer rhenium diselenide (ReSe2) FETs encapsulated between h-BN flakes at V g = 47 V. The high mobility is attributed to low-resistance contacts of scandium/gold (Sc/Au), with a low Schottky barrier height and reduced charge scattering platform of h-BN. Further, we elucidated the Schottky-barrier-height dependent high photoresponsivity (∼3.2 × 106 A W-1) of few-layer ReSe2 (FL-ReSe2) at 532 nm-wavelength laser light on an h-BN substrate with Sc/Au contacts. Moreover, broadband light detection of undoped and Co-doped few-layer (FL) ReSe2 was performed under different laser wavelengths (400-1100 nm). After the deposition of Co nanoparticles, the photocurrent of FL-ReSe2 increased due to n-doping, as confirmed by the transfer curves of the FL-ReSe2-based undoped and co-doped FETs. Further, the work function decreased from 4.856 to 4.791 eV in FL-ReSe2, as measured by Kelvin probe force microscopy. No light signal was observed at 1100 nm for the undoped ReSe2 (1050 nm < λ cut-off < 1100 nm); however, after doping with Co nanoparticles, the cut-off wavelength exceeded to (λ cut-off > 1100 nm), due to the additional trap states generated in the energy band gap of ReSe2 after Co doping. Further, the transient response of ReSe2 and Co + ReSe2 FETs was estimated so that the rise and decay times are decreased from 1.9 s & 2.7 s to 1.1 s & 1.8 s, respectively. ReSe2 is therefore a promising semiconducting material for electrical and optoelectrical applications.
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| 24. |
- Naqvi, Muhammad, et al.
(författare)
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An experimental study on hydrogen enriched gas with reduced tar formation using pre-treated olivine in dual bed steam gasification of mixed biomass compost
- 2016
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Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 41:25, s. 10608-10618
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Tidskriftsartikel (refereegranskat)abstract
- The study investigated the effects of pre-treated olivine in dual bed steam gasification (DBSG) of biomass compost in order to produce H-2 enriched synthesis gas with significantly reduced tar formation. The DBSG employed circulating fluidized bed (CFB) of silica sand as first stage and fixed catalytic bed of pre-treated olivine as second stage. The mixed biomass compost contained 15-20 wt. % of agri-residues (mainly wheat straw) and 80-85 wt. % of cow manure. The study compared the synthesis gas distribution and tar reductions using pre-treated olivine in the DBSG scheme with Ni-Al based DBSG scheme. The effects of operating condition on the synthesis gas distribution and tar formation are studied such as: (i) effect of steam to biomass ratio, (ii) effects of relative oxidation (relox), (iii) operating temperature of the reactor, (iv) performance and comparison of employed catalysts, and (v) yield of synthesis gas together with carbon conversion efficiency. Experimental analysis showed that H-2 concentration obtained from pre-treated olivine based DBSG is considerably higher than H-2 produced from compared gasification schemes. The H-2 production is favoured at higher temperatures and higher SBR under the influence of pre-treated olivine catalyst. However, the conditions are less advantageous for the production of CO and CH4. Among all experiments, the synthesis gas composition obtained at SBR = 1.40 and at 800 degrees C consisted of highest H-2 concentration (35 vol.% d.n.f) in the pre-treated olivine DBSG. Higher steam to biomass ratio (SBR) resulted in lower cold gas energy efficiency and lower heating value of the synthesis gas mainly due to large steam content in the gas. The tar removal efficiency of 98% is achieved with the pre-treated olivine DBSG system. The total tar content is significantly reduced (approximate to 40%) in the DBSG with pre-treated olivine. Higher relative oxidation resulted in increased concentration of CO2 in the synthesis gas due to increased partial oxidation of organic matter in the gasifier. The pre-treated olivine catalyst in the DBSG consistently promoted the process of steam reforming and tar cracking and thus improved the quality of the syngas by limiting the tar contents. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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| 25. |
- Naqvi, Muhammad, et al.
(författare)
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Gasification integrated with small chemical pulp mills for fuel and energy production
- 2017
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Ingår i: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY. - : Elsevier. ; 142, s. 977-983
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Konferensbidrag (refereegranskat)abstract
- Pulp mills without black liquor recovery cycle could play a major role in employing black liquor gasification (BLG) to produce transport fuels. In conventional chemical pulp mills, black liquor is burnt in recovery boilers to generate steam and electricity to meet energy demands. The inorganic chemicals are reused for the digestion process. However, the energy content and inorganic chemicals are not recovered in small scale pulp mills especially in the developing countries which do not employ recovery cycle. This study investigates the potential of synthetic natural gas (SNG) production by integrating BLG island with a reference pulp mill without chemical recovery cycle. The improvements in overall energy efficiency are evaluated using performance indicators such as biofuel production potential, integrated system's efficiency, and energy ratios. The oxygen-blown circulating fluidized bed (CFB) gasification with direct causticization is integrated with reference pulp mill. The results showed considerable SNG production without external biomass import. However to compensate total electricity deficit, the electricity will be imported from the grid. There is a substantial CO2 abatement potential of combining CO2 capture using seloxol absorption, and CO2 mitigation from SNG by replacing gasoline. (C) 2017 The Authors. Published by Elsevier Ltd.
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