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Sökning: WFRF:(Naqvi Muhammad)

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1.
  • Ademuyiwa, Adesoji O., et al. (författare)
  • Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
  • 2016
  • Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
  • 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.
  • Usman, Muhammad, et al. (författare)
  • Use of Gasoline, LPG and LPG-HHO Blend in SI Engine : A Comparative Performance for Emission Control and Sustainable Environment
  • 2020
  • Ingår i: Processes. - : MDPI. - 2227-9717. ; 8:1
  • 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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3.
  • 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
  • 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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4.
  • Naqvi, Salman Raza, et al. (författare)
  • Agro-industrial residue gasification feasibility in captive power plants : A South-Asian case study
  • 2021
  • Ingår i: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 214
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective of this study is to build knowledge on the potential of agro-industrial residue gasification (AIRG) for use in captive power generation through a comprehensive case study. In order to evaluate the economic viability, key performance indicators, such as net present value (NPV), levelized cost of electricity (LCOE), and operating costs etc. are studied. The major textile industry located in the Raiwind area of Punjab province of Pakistan has been selected. The effect and variations of the capacity factor has also been studied coupled with the levelized cost of electricity. The agricultural residue as feedstock to the gasifier is rice husk that is the abundantly available in South Asia. Furthermore, the impact of government subsidies on natural gas is also under the scope of the study. The agro-industrial residue gasification system is found to be a potential alternative to furnace oil (FO) or gas-based captive power plants (CPPs). The results of residue-based gasification system imply a large potential when comparing the cost of electricity with national grid electricity during the peak hours. Therefore, the proposed gasification system offers economic incentives when the textile industry potentially utilizes gasification-based electricity during peak hours and national grid electricity during off-peak hours. (C) 2020 Elsevier Ltd. All rights reserved.
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5.
  • Naqvi, Salman Raza, et al. (författare)
  • Potential of biomass for bioenergy in Pakistan based on present case and future perspectives
  • 2018
  • Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 81:1, s. 1247-1258
  • 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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6.
  • Arslan, Muhammad, et al. (författare)
  • Impact of Varying Load Conditions and Cooling Energy Comparison of a Double-Inlet Pulse Tube Refrigerator
  • 2020
  • 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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7.
  • Naqvi, Salman Raza, et al. (författare)
  • Recent developments on sewage sludge pyrolysis and its kinetics : Resources recovery, thermogravimetric platforms, and innovative prospects
  • 2021
  • Ingår i: Computers and Chemical Engineering. - : Elsevier. - 0098-1354 .- 1873-4375. ; 150
  • Tidskriftsartikel (refereegranskat)abstract
    • Sewage sludge is a by-product of the wastewater treatment process, which has the potential to be a source of transport fuels, heat, and power using the pyrolysis process. Considering the prevalence and disposal issues associated with sewage sludge, the objective of this study is to critically review the recent advancements in sewage sludge pyrolysis and its kinetics obtained using the thermogravimetric techniques, and other associated different kinetic models documented in the literature. The study will identify optimum operating conditions and design parameters to obtain high yields. The state-of-the-art perspectives and the challenges associated with full-scale implementation are highlighted for biofuels and resource recovery from the sewage sludge. Furthermore, machine-learning approaches in thermal kinetics of pyrolysis are presented and discussed in terms of their effectiveness in predicting thermal kinetics data. Finally, the challenges for a successful implementation and commercial viability of sewage sludge pyrolysis are discussed.
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8.
  • Ali, Imtiaz, et al. (författare)
  • Kinetic and thermodynamic analyses of dried oily sludge pyrolysis
  • 2021
  • Ingår i: Journal of the Energy Institute. - : Elsevier. - 1743-9671 .- 1746-0220. ; 95, s. 30-40
  • Tidskriftsartikel (refereegranskat)abstract
    • Oily sludge has the potential to utilize in pyrolysis process effectively because of higher product recovery and lower harmful emissions. Due to the complex nature of reactions, it is necessary to evaluate the thermo-kinetic behavior of the process to make it commercially feasible. This study includes thermal degradation behavior, the kinetic and thermodynamic analysis of dry oily sludge by applying Friedman and Vyazovkin method (model-free approach), and Coats-Redfern method (model-fitting approach) with the help of thermogravimetric analysis TGA at different heating rates (5, 20, 40 °C/min). The active region was from 20 to 60% conversion range because the maximum conversion occurs in this region. The overall activation energy decreases as the conversion increases from a lower range (60%) to a higher range (80%) for all satisfied models. The estimated range of pre-exponential coefficient for each model was to 4.91E+15 to 2.30E-01min−1 in the conversion range of 20–60% and 9.80E+02 to 4.89E-04min−1 in the conversion range 60–80%. The overall value of the change in enthalpy ΔH and change in Gibbs free energy ΔG decrease as the conversion increases from the lower range to the higher range.
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9.
  • Anees, Hafiz Muhammad, et al. (författare)
  • A mathematical model-based approach for DC multi-microgrid performance evaluations considering intermittent distributed energy resources, energy storage, multiple load classes, and system components variations
  • 2021
  • Ingår i: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; 9, s. 1919-1934
  • Tidskriftsartikel (refereegranskat)abstract
    • The efficiency of DC microgrid needs investigation from a smart grid perspective, since their spread has expected to prevail in comparison with AC counterparts. Furthermore, there is a need to address the limitations (majorly to cater the intermittency of distributed energy resources (DERs) as well as the time dependency of systematic parameters etc.) in previous model and propose a new mathematical model to evaluate system efficiency for given parameters and scenarios. The core focus of current study aims at formulation of an improved (composite) mathematical model, that is capable of bridging issues and serve as a tool to address requirements of future DC systems including microgrids (MGs) and multi-microgrids (MMGs). This research work offers such a mathematical model that consists of 3D matrices based on newly derived set of discrete time dependent equations, which evaluates the system efficiency of residential DC-MMGs. Each DC-MG is embedded with intermittent DERs, storage, components (with efficiency variations), and multi-class load (with discrete time dependency), for evaluation across worst, normal, and best scenarios. A comprehensive sensitivity analysis across various cases and respective scenarios are also presented to evaluate overall system performance. Also, the impacts of system parameters on various system variables, states, and overall system efficiency have presented in this paper.
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10.
  • Danish, Muhammad, et al. (författare)
  • Characterization of South Asian agricultural residues for potential utilization in future 'energy mix'
  • 2015
  • Ingår i: Energy Procedia. - : Elsevier. ; 75, s. 2974-2980
  • 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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11.
  • Danish, Muhammad, et al. (författare)
  • Role of reactive oxygen species and effect of solution matrix in trichloroethylene degradation from aqueous solution by zeolite-supported nano iron as percarbonate activator
  • 2016
  • Ingår i: Research on chemical intermediates (Print). - : Springer. - 0922-6168 .- 1568-5675. ; 42:9, s. 6959-6973
  • Tidskriftsartikel (refereegranskat)abstract
    • The role of reactive oxygen species (ROSs) and effect of solution matrix have been investigated for the degradation of trichloroethylene (TCE). Zeolite-supported nano iron (Z-nZVI) was synthesized as an activator to catalyze sodium percarbonate (SPC) with or without hydroxylamine, i.e. as reducing agent (RA). The probe tests confirmed the generation of OH center dot and O-2(-center dot) in the Z-nZVI activated SPC system in absence of the RA, while the presence of RA significantly increased the generation of OH center dot and O-2(-center dot) radicals. Scavenger tests demonstrated that OH center dot was the main ROS responsible for TCE degradation, whereas O-2(-center dot) also participated in TCE degradation. From the solution matrix perspective, the experimental results confirmed significant scavenging effects of Cl- (1.0, 10.0, and 100 mmol L-1) and HCO3- (1.0 and 10.0 mmol L-1), whereas the scavenging effects were fairly impeded at 100 mmol L-1 concentration of HCO3-. On the other hand, a considerable decline in scavenging effect was observed in the presence of RA in tested Cl and HCO3- concentration ranges. In addition, negligible scavenging effects of NO3- and SO42- anions were found in all tested concentrations. The effect of initial solution pH on catalytic activity indicated a significant increase in the TCE degradation in the presence of RA even at higher pH value of 9. The results indicated that the Z-nZVI activated SPC system in presence of RA can effectively degrade chlorinated organic solvents, but it is important to consider the intensive existence of anions in groundwater.
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12.
  • Farooq, Usman, et al. (författare)
  • Synthesis of nZVI@reduced graphene oxide : an efficient catalyst for degradation of 1,1,1-trichloroethane (TCA) in percarbonate system
  • 2017
  • Ingår i: Research on chemical intermediates (Print). - : SPRINGER. - 0922-6168 .- 1568-5675. ; 43:5, s. 3219-3236
  • 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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13.
  • Hussain, Arif, et al. (författare)
  • Methoxy-methylheptane as a cleaner fuel additive : An energy- and cost-efficient enhancement for separation and purification units
  • 2021
  • Ingår i: Energy Science & Engineering. - : John Wiley & Sons. - 2050-0505. ; :9, s. 1632-1646
  • Tidskriftsartikel (refereegranskat)abstract
    • Environmental protection agencies have begun imposing stringent regulations on the existing refineries to control the levels of gasoline additives. In this context, a novel compound, 2-methoxy-2-methylheptane (MMH), had drawn attention as fuel additive for cleaner combustion. The conventional process of MMH production features three distillation columns in a direct sequence. These columns are used to maintain the required product purities and to utilize the unreacted reactants through recycling streams. The distillation system of the existing MMH plant can afford significant energy savings, leading to a reduction in the total annual costs (TAC). The aim of this investigation is to demonstrate that the reported conventional process can be significantly enhanced by modifying the design and operational parameters and by replacing two distillation columns with an intensified dividing wall column (DWC) configuration. The DWC design is further optimized using several algorithms such as the modified coordinate method (MCD), robust particle swarm paradigm (PSP), and firefly (FF) with nonlinear constraints. Compared to conventional process, the optimized DWC resulted in 24% and 11.5% savings in the plant operating and total annual costs, respectively.
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14.
  • Kazmi, Bilal, et al. (författare)
  • Thermodynamic and economic assessment of cyano functionalized anion based ionic liquid for CO2 removal from natural gas integrated with, single mixed refrigerant liquefaction process for clean energy
  • 2022
  • Ingår i: Energy. - : Pergamon Press. - 0360-5442 .- 1873-6785. ; 239
  • Tidskriftsartikel (refereegranskat)abstract
    • The study proposes a novel integrated process in which ionic liquid is utilized to control carbon dioxide (CO2) emissions from the natural gas combined with a single mixed refrigerant-based liquefaction process to assist safe transportation over long distances providing a sustainable and cleaner energy. Commercially amines are utilized for CO2 sequestration, but amines entail energy-intensive regeneration with elevated process costs. The present study offers a solvent screening mechanism based on important parameters such as heat of dissolution, viscosity, selectivity, working capacity, vapor pressure, corrosivity, and toxicity. The selected solvents' performance is computed by sensitivity analysis suggesting imidazolium-based cation 1-hexyl-3-methylimidazolium[Hmim] functionalized with tricyanomethanide(tcm) as anion a potential natural gas sweetening solvent in comparison with commercially used solvent monoethanoloamine(MEA), conventional ILs 1-butyl-3-methylimidazolium hexa-fluorophosphate [Bmim][Pf(6)] and 1-butyl-3-methylimidazolium methyl sulfate [Bmim][MeSO4]. The obtained sweet gas is liquefied using a single mixed refrigerant-based process providing 0.99 mol fraction of liquefied CH4 with less overall specific compression power requirement of 0.41 kW/kg of natural gas. Moreover, an exergy analysis demonstrates that the [Hmim][tcm] based process has lower total exergy destruction of 7.49 x 10(3) kW and is found to utilize less overall specific energy consumption 0.49 kWh/kg of NG in contrast to other studied solvents. Furthermore, a detailed economic analysis establishes [Hmim][tcm]-based CO2 integrated with liquefaction technology offers 50.7%, 74.4%, and 85.8% of total annualized cost (TAC) savings compared with the MEA-amim][Pf(6)]-, and [Bmim][MeSO4], respectively. Hence, [Hmim][tcm] for CO2 removal and integration with liquefaction process will incur unit cost based on the total annualized cost to be $2.2 x 10(4)/kmol of purified NG.
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15.
  • Manzoor, Numair, et al. (författare)
  • RETRACTED: Experimental Study of CO2 Conversion into Methanol by Synthesized Photocatalyst (ZnFe2O4/TiO2) Using Visible Light as an Energy Source
  • 2020
  • Ingår i: Catalysts. - : MDPI. - 2073-4344. ; 10:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Ozone layer depletion is a serious threat due to the extensive release of greenhouse gases. The emission of carbon dioxide (CO2) from fossil fuel combustion is a major reason for global warming. Energy demands and climate change are coupled with each other. CO2is a major gas contributing to global warming; hence, the conversion of CO2 into useful products such as methanol, formic acid, formaldehyde, etc., under visible light is an attractive topic. Challenges associated with the current research include synthesizing a photocatalyst that is driven by visible light with a narrow band gap range between 2.5 and 3.0 eV, the separation of a mixed end product, and the two to three times faster recombination rate of an electron–hole pair compared with separation over yield. The purpose of the current research is to convert CO2 into useful fuel i.e., methanol; the current study focuses on the photocatalytic reduction of CO2into a useful product. This research is based on the profound analysis of published work, which allows the selection of appropriate methods and material for this research. In this study, zinc ferrite (ZnFe2O4) is synthesized via the modified sol–gel method and coupled with titanium dioxide (TiO2). Thereafter, the catalyst is characterized by Fourier transform infrared (FTIR), FE-SEM, UV–Vis, and XRD characterization techniques. UV–Vis illustrates that the synthesized catalyst has a low band gap and utilizes a major portion of visible light irradiation. The XRD pattern was confirmed by the formation of the desired catalyst. FE-SEM illustrated that the size of the catalyst ranges from 50 to 500 nm and BET analysis determined the surface area, which was 2.213 and 6.453 m2/g for ZnFe2O4 and ZnFe2O4/TiO2, respectively. The continuous gas flow photoreactor was used to study the activity of the synthesized catalyst, while titanium dioxide (TiO2) has been coupled with zinc ferrite (ZnFe2O4) under visible light in order to obtain the maximum yield of methanol as a single product and simultaneously avoid the conversion of CO2 into multiple products. The performance of ZnFe2O4/TiO2was mainly assessed through methanol yield with a variable amount of TiO2 over ZnFe2O4 (1:1, 1:2, 2:1, 1:3, and 3:1). The synthesized catalyst recycling ability has been tested up to five cycles. Finally, we concluded that the optimum conditions for maximum yield were found to be a calcination temperature of ZnFe2O4at 900 °C, and optimum yield was at a 1:1 w/w coupling ratio of ZnFe2O4/TiO2. It was observed that due to the enhancement in the electron–hole pair lifetime, the methanol yield at 141.22 μmol/gcat·h over ZnFe2O4/TiO2was found to be 7% higher than the earlier reported data.
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16.
  • Mehran, Muhammad Taqi, et al. (författare)
  • A comprehensive review on durability improvement of solid oxide fuel cells for commercial stationary power generation systems
  • 2023
  • Ingår i: Applied Energy. - 1872-9118 .- 0306-2619. ; 352
  • Tidskriftsartikel (refereegranskat)abstract
    • Solid oxide fuel cells (SOFCs) are recognized as an alternative for power generation applications due to their high efficiency and environment-friendly behaviour. The electronic devices and power age could be revolutionized with the commercialization of such devices. Stationary power generation systems based on SOFCs are a step closer to commercialization due to the latest developments in the technology that promises to overcome the inherent bottleneck of high-temperature fuel cells, i.e., durability. According to the US Department of Energy (DOE), the stationary power generation system should have a lifetime of 40,000 h continuous operation. The efficiency of SOFCs is mainly dependent on their components such as anode, cathode, interconnect, and electrolyte. There are numerous factors affecting the efficiency of SOFCs that include the composition of the fuel, kinetics, and thermodynamics of the cell, and working temperature. In this paper, we have presented a comprehensive review of the recent developments to produce durable SOFCs for commercial stationary power generation systems. The review summarizes several prominent degradation mechanisms involved in the SOFC components and methods to reduce the degradation process. In addition, the methods and techniques adopted for the degradation analysis are fully demonstrated, followed by a detailed durability diagnostic through in-situ and ex-situ durability testing. The review is complemented by a lucid presentation of future research challenges and the knowledge gaps coupled with potential recommendations to fill the gaps. The new engineering designs, the material development and the new knowledge presented in this study could provide useful guidance for the key stakeholders, policymakers and power generation entities to commercially implement the application of durable SOFCs for stationary power generation.
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17.
  • Naqvi, Muhammad, et al. (författare)
  • Gasification integrated with small chemical pulp mills for fuel and energy production
  • 2017
  • Ingår i: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY. - : Elsevier. ; 142, s. 977-983
  • 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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18.
  • Naqvi, Syeda, I, et al. (författare)
  • An Integrated Antenna System for 4G and Millimeter-Wave 5G Future Handheld Devices
  • 2019
  • Ingår i: IEEE Access. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 2169-3536. ; 7, s. 116555-116566
  • Tidskriftsartikel (refereegranskat)abstract
    • In this work, an integrated antenna system with Defected Ground Structure (DGS) is presented for Fourth Generation (4G) and millimeter (mm)-wave Fifth Generation (5G) wireless applications and handheld devices. The proposed design with overall dimensions of 110 mm x 75 mm is modeled on 0.508 mm thick Rogers RT/Duroid 5880 substrate. Radiating structure consists of antenna arrays excited by the T-shape 1 x 2 power divider/combiner. Dual bands for 4G centered at 3.8 GHz and 5.5 GHz are attained, whereas the 10-dB impedance bandwidth of 24.4 - 29.3 GHz is achieved for the 5G antenna array. In addition, a peak gain of 5.41 dBi is demonstrated across the operating bandwidth of the 4G antenna array. Similarly, for the 5G mm-wave configuration the attained peak gain is 10.29 dBi. Moreover, significant isolation is obtained between the two antenna modules ensuring efficient dual-frequency band operation using a single integrated solution. To endorse the concept, antenna prototype is fabricated and far-field measurements are procured. Simulated and measured results exhibit coherence. Also the proposed design is investigated for the beam steering capability of the mm-wave 5G antenna array using CST(R)MWS(R). The demonstrated structure offers various advantages including compactness, wide bandwidth, high gain, and planar configuration. Hence, the attained radiation characteristics prove the suitability of the proposed design for the current and future wireless handheld devices.
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19.
  • Naqvi, Salman Raza, et al. (författare)
  • New trends in improving gasoline quality and octane through naphtha isomerization : a short review
  • 2018
  • Ingår i: APPLIED PETROCHEMICAL RESEARCH. - : Springer. - 2190-5533 .- 2190-5533 .- 2190-5525. ; 8:3, s. 131-139
  • Forskningsöversikt (refereegranskat)abstract
    • The octane enhancement of light straight run naphtha is one of the significant solid acid catalyzed processes in the modern oil refineries due to limitations of benzene, aromatics, and olefin content in gasoline. This paper aims to examine the role of various catalysts that are being utilized for the isomerization of light naphtha with an ambition to give an insight into the reaction mechanism at the active catalyst sites, and the effect of various contaminants on catalyst activity. In addition, different technologies used for isomerization process are evaluated and compared by different process parameters.
  •  
20.
  • Naqvi, Salman Raza, et al. (författare)
  • Pyrolysis of high ash sewage sludge : Kinetics and thermodynamic analysis using Coats-Redfern method
  • 2019
  • Ingår i: Renewable energy. - : Elsevier Ltd. - 0960-1481 .- 1879-0682. ; 131, s. 854-860
  • Tidskriftsartikel (refereegranskat)abstract
    • This study aims to investigate the thermo-kinetics of high-ash sewage sludge using thermogravimetric analysis. Sewage sludge was dried, pulverized and heated non-isothermally from 25 to 800 °C at different heating rates (5, 10 and 20 °C/min) in N2 atmosphere. TG and DTG results indicate that the sewage sludge pyrolysis may be divided into three stages. Coats-Redfern integral method was applied in the 2nd and 3rd stage to estimate the activation energy and pre-exponential factor from mass loss data using five major reaction mechanisms. The low-temperature stable components (LTSC) of the sewage sludge degraded in the temperature regime of 250–450 °C while high-temperature stable components (HTSC) decomposed in the temperature range of 450–700 °C. According to the results, first-order reaction model (F1) showed higher Ea with better R2 for all heating rates. D3, N1, and S1 produced higher Ea at higher heating rates for LTSC pyrolysis and lower Ea with the increase of heating rates for HTSC pyrolysis. All models showed positive ΔH except F1.5. Among all models, Diffusion (D1, D2, D3) and phase interfacial models (S1, S2) showed higher ΔG as compared to reaction, nucleation, and power-law models in section I and section II.
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21.
  • Naveed, Muhammad Hamza, et al. (författare)
  • Cellulosic biomass fermentation for biofuel production : Review of artificial intelligence approaches
  • 2024
  • Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 189
  • Tidskriftsartikel (refereegranskat)abstract
    • Scarcity in fossil fuel reserves and their environmental impacts has forced the world towards the production of clean and environment-friendly fuels called biofuels. This review focuses on the importance of different machine learning models and optimization techniques to simulate and optimize process conditions, yield and parameters in the fermentation of cellulosic biomass from fifty recent studies. The superiority of ML models, especially ANN dominance in 70 % of studies with highest coefficient of regression over conventional techniques in the production of bioethanol and biohydrogen is comprehensively reviewed. Research gaps and studies directed toward the usage of most optimum ML models in future are directed after the sensitivity analysis with 5 % variation that suggest the stability of ML models. It is intended to spur further investigation into the development and use of ML models combined with optimization methods and CFD in the fermentation process to produce bioethanol and biohydrogen. 
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22.
  • Qureshi, Abdul Sattar, et al. (författare)
  • Fruit waste to energy through open fermentation
  • 2017
  • Ingår i: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY. - Amsterdam : Elsevier. ; 142, s. 904-909
  • Konferensbidrag (refereegranskat)abstract
    • This study aims to examine the nonsterilized fermentation conditions for coproduction of pectinases and lipase enzymes using several fruit wastes as an energy source. Thermophilic fungal strain, Penicillium expansum CM,1 39671 was used as a fermenting strain. The effect of process conditions including; nitrogen sources, pH, temperature, time and moisture contents, on the production of both enzymes were studied. The highest activities of pectinase and lipase (2817, 1870 U/g dry substrate) enzymes were found with orange peel feedstock, whereas the lowest activities of 1662 U/g and 1266 U/g were found with banana peel and papaya peel feedstocks respectively. Overall, pectinase showed higher enzymatic activities than lipase enzymes, both having similar increasing and decreasing trends, at all studied conditions. The optimum process conditions of peptone as a nitrogen source, pH 7, 40 degrees C, 5 days and 70% moisture contents, were found to show highest enzymatic activities for both enzymes. The orange peel feedstock showed no significant difference in both enzymes' activities at sterilized and nonnotarized process conditions. Pectinase and lipase enzymes showed (13791 U/g) and (8114 U/g) for sterilized and (14091 U/g) and (8324 U/g) for nonnotarized process conditions respectively. In addition, the fungal strains also produce bacteriocin-like compounds that could inhibit microbial growth. These findings will help to design and develop robust, cost-effective and less energy intensive enzyme production processes and consequently an efficient fruit waste to energy system through open fermentation. (C) 2017 The Authors. Published by Elsevier Ltd.
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23.
  • Abbas, Shahrukh, et al. (författare)
  • Impact Analysis of Large-Scale Wind Farms Integration in Weak Transmission Grid from Technical Perspectives
  • 2020
  • Ingår i: Energies. - : MDPI. - 1996-1073. ; 13:20
  • Tidskriftsartikel (refereegranskat)abstract
    • The integration of commercial onshore large-scale wind farms into a national grid comes with several technical issues that predominately ensure power quality in accordance with respective grid codes. The resulting impacts are complemented with the absorption of larger amounts of reactive power by wind generators. In addition, seasonal variations and inter-farm wake effects further deteriorate the overall system performance and restrict the optimal use of available wind resources. This paper presented an assessment framework to address the power quality issues that have arisen after integrating large-scale wind farms into weak transmission grids, especially considering inter-farm wake effect, seasonal variations, reactive power depletion, and compensation with a variety of voltage-ampere reactive (Var) devices. Herein, we also proposed a recovery of significant active power deficits caused by the wake effect via increasing hub height of wind turbines. For large-scale wind energy penetration, a real case study was considered for three wind farms with a cumulative capacity of 154.4 MW integrated at a Nooriabad Grid in Pakistan to analyze their overall impacts. An actual test system was modeled in MATLAB Simulink for a composite analysis. Simulations were performed for various scenarios to consider wind intermittency, seasonal variations across four seasons, and wake effect. The capacitor banks and various flexible alternating current transmission systems (FACTS) devices were employed for a comparative analysis with and without considering the inter-farm wake effect. The power system parameters along with active and reactive power deficits were considered for comprehensive analysis. Unified power flow controller (UPFC) was found to be the best compensation device through comparative analysis, as it maintained voltage at nearly 1.002 pu, suppressed frequency transient in a range of 49.88-50.17 Hz, and avoided any resonance while maintaining power factors in an allowable range. Moreover, it also enhanced the power handling capability of the power system. The 20 m increase in hub height assisted the recovery of the active power deficit to 48%, which thus minimized the influence of the wake effect.
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24.
  • Afroz, Laila, et al. (författare)
  • Nanocomposite Catalyst (1 – x)NiO-xCuO/yGDC for Biogas Fueled Solid Oxide Fuel Cells
  • 2023
  • Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 6:21, s. 10918-10928
  • 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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25.
  • Azeem, Babar, et al. (författare)
  • Production and Characterization of Controlled Release Urea Using Biopolymer and Geopolymer as Coating Materials
  • 2020
  • Ingår i: Polymers. - : MDPI. - 2073-4360. ; 12:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Synthetic polymers-based controlled release urea (CRU) leaves non-biodegradable coating shells when applied in soil. Several alternative green materials are used to produce CRU, but most of these studies have issues pertaining to nitrogen release longevity, process viability, and the ease of application of the finished product. In this study, we utilized tapioca starch, modified by polyvinyl alcohol and citric acid, as coating material to produce controlled release coated urea granules in a rotary fluidized bed equipment. Response surface methodology is employed for studying the interactive effect of process parameters on urea release characteristics. Statistical analysis indicates that the fluidizing air temperature and spray rate are the most influential among all five process parameters studied. The optimum values of fluidizing air temperature (80 degrees C), spray rate (0.13 mL/s), atomizing pressure (3.98 bar), process time (110 min), and spray temperature (70 degrees C) were evaluated by multi-objective optimization while using genetic algorithms in MATLAB((R)). Urea coated by modified-starch was double coated by a geopolymer to enhance the controlled release characteristics that produced promising results with respect to the longevity of nitrogen release from the final product. This study provides leads for the design of a fluidized bed for the scaled-up production of CRU.
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26.
  • Danish, Muhammad, et al. (författare)
  • An efficient catalytic degradation of trichloroethene in a percarbonate system catalyzed by ultra-fine heterogeneous zeolite supported zero valent iron-nickel bimetallic composite
  • 2017
  • Ingår i: Applied Catalysis A. - : Elsevier. - 0926-860X .- 1873-3875. ; 531, s. 177-186
  • 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.
  •  
27.
  • Danish, Muhammad, et al. (författare)
  • Degradation of chlorinated organic solvents in aqueous percarbonate system using zeolite supported nano zero valent iron (Z-nZVI) composite
  • 2016
  • Ingår i: Environmental Science and Pollution Research. - : Springer. - 0944-1344 .- 1614-7499. ; 23:13, s. 13298-13307
  • Tidskriftsartikel (refereegranskat)abstract
    • Chlorinated organic solvents (COSs) are extensively detected in contaminated soil and groundwater that pose long-term threats to human life and environment. In order to degrade COSs effectively, a novel catalytic composite of natural zeolite-supported nano zero valent iron (Z-nZVI) was synthesized in this study. The performance of Z-nZVI-catalyzed sodium percarbonate (SPC) in a heterogeneous Fenton-like system was investigated for the degradation of COSs such as 1,1,1-trichloroethane (1,1,1-TCA) and trichloroethylene (TCE). The surface characteristics and morphology of the Z-nZVI composite were tested using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Total pore volume, specific surface area, and pore size of the natural zeolite and the Z-nZVI composite were measured using Brunauer-Emmett-Teller (BET) method. SEM and TEM analysis showed significant elimination of aggregation and well dispersion of iron nano particles on the framework of natural zeolite. The BET N-2 measurement analysis indicated that the surface area of the Z-nZVI composite was 72.3 m(2)/g, much larger than that of the natural zeolite (0.61 m(2)/g). For the contaminant analysis, the samples were extracted with n-hexane and analyzed through gas chromatograph. The degradation of 1,1,1-TCA and TCE in the Z-nZVI-catalyzed percarbonate system were 48 and 39 % respectively, while strong augmentation was observed up to 83 and 99 %, respectively, by adding the reducing agent (RA), hydroxyl amine (NH2OH center dot HCl). Probe tests validated the presence of OH center dot and O-2(center dot-) which were responsible for 1,1,1-TCA and TCE degradation, whereas both free radicals were strengthened with the addition of RA. In conclusion, the Z-nZVI/SPC oxidation with reducing agent shows potential technique for degradation of groundwater contaminated by 1,1,1-TCA and TCE.
  •  
28.
  • Danish, Muhammad, et al. (författare)
  • 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
  • Ingår i: Water Science and Technology. - London, UK : IWA PUBLISHING. - 1606-9749 .- 1607-0798. ; 17:6, s. 1568-1578
  • 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.
  •  
29.
  • Danish, Muhammad, et al. (författare)
  • Efficient transformation of trichloroethylene activated through sodium percarbonate using heterogeneous zeolite supported nano zero valent iron-copper bimetallic composite
  • 2017
  • Ingår i: Chemical Engineering Journal. - : Elsevier. - 1385-8947 .- 1873-3212. ; 308, s. 396-407
  • 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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30.
  • Hameed, Zeeshan, et al. (författare)
  • A Comprehensive Review on Thermal Coconversion of Biomass, Sludge, Coal, and Their Blends Using Thermogravimetric Analysis
  • 2020
  • Ingår i: Journal of Chemistry. - : Hindawi Publishing Corporation. - 2090-9063 .- 2090-9071. ; 2020
  • Forskningsöversikt (refereegranskat)abstract
    • Lignocellulosic biomass is a vital resource for providing clean future energy with a sustainable environment. Besides lignocellulosic residues, nonlignocellulosic residues such as sewage sludge from industrial and municipal wastes are gained much attention due to its large quantities and ability to produce cheap and clean energy to potentially replace fossil fuels. These cheap and abundantly resources can reduce global warming owing to their less polluting nature. The low-quality biomass and high ash content of sewage sludge-based thermal conversion processes face several disadvantages towards its commercialization. Therefore, it is necessary to utilize these residues in combination with coal for improvement in energy conversion processes. As per author information, no concrete study is available to discuss the synergy and decomposition mechanism of residues blending. The objective of this study is to present the state-of-the-art review based on the thermal coconversion of biomass/sewage sludge, coal/biomass, and coal/sewage sludge blends through thermogravimetric analysis (TGA) to explore the synergistic effects of the composition, thermal conversion, and blending for bioenergy production. This paper will also contribute to detailing the operating conditions (heating rate, temperature, and residence time) of copyrolysis and cocombustion processes, properties, and chemical composition that may affect these processes and will provide a basis to improve the yield of biofuels from biomass/sewage sludge, coal/sewage sludge, and coal/biomass blends in thermal coconversion through thermogravimetric technique. Furthermore, the influencing factors and the possible decomposition mechanism are elaborated and discussed in detail. This study will provide recent development and future prospects for cothermal conversion of biomass, sewage, coal, and their blends.
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31.
  • Jamil, Asif, et al. (författare)
  • Polyetherimide-Montmorillonite Nano-Hybrid Composite Membranes : CO2 Permeance Study via Theoretical Models
  • 2020
  • Ingår i: Processes. - : MDPI. - 2227-9717. ; 8:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The incorporation of aminolauric acid modified montmorillonite (f-MMT) in polyetherimide (PEI) has been implemented to develop hollow fibre nano-hybrid composite membranes (NHCMs) with improved gas separation characteristics. The aforementioned characteristics are caused by enhanced f-MMT spatial dispersion and interfacial interactions with PEI matrix. In this study, existing gas permeation models such as, Nielsen, Cussler, Yang-Cussler, Lape-Cussler and Bharadwaj were adopted to estimate the dispersion state of f-MMT and to predict the CO2 permeance in developed NHCMs. It was found out that the average aspect ratio estimated was 53, with 3 numbers of stacks per unit tactoid, which showed that the intercalation f-MMT morphology is the dominating dispersion state of filler in PEI matrix. Moreover, it was observed that Bharadwaj model showed the least average absolute relative error (%AARE) values till 3 wt. % f-MMT loading in the range of +/- 10 for a pressure range of 2 to 10 bar. Hence, Bharadwaj was the best fit model for the experimental data compared to other models, as it considers the platelets orientation.
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32.
  • Kazmi, Bilal, et al. (författare)
  • Process system analysis on oil processing facility and economic viability from oil well-to-tank
  • 2021
  • Ingår i: SN Applied Sciences. - : Springer Science and Business Media LLC. - 2523-3963 .- 2523-3971. ; 3:7
  • Tidskriftsartikel (refereegranskat)abstract
    • Hydrocarbon processing from extraction to the final product is an important aspect that needs an optimised technology for consumption-led market growth. This study investigated real data from the oil processing facility and analysed the simulation model for the entire crude oil processing unit based on the process system engineering aspect using Aspen HYSYS. The study mainly emphasises the process optimisation in processing the hydrocarbon for the maximum yield of the product with less energy consumption. The investigation also includes a thorough economic analysis of the processing facility. The datasets for oil properties are obtained from a modern petroleum refinery. The investigation comprises of varying transient conditions, such as well shutdowns using three oil reservoirs (low, intermediate, and heavy oil). The impact of various conditions, including process heating, well shutdown, oil combinations, presence of water on the production, is analysed. The results indicate that the factors involving crude oil processing are significantly affected by the process conditions, such as pressure, volume, and temperature. The vapour recovery unit is integrated with the oil processing model to recover the separator's gas. The optimisation analysis is performed to maximise the liquid recovery with Reid vapour pressure of 7 and minimum water content in oil around 0.5%. Economic analysis provided an overall capital cost of $ 9.7 x 10(6) and an operating cost of $2.1 x 10(6) for the process configuration. The model results further investigate the constraints that maximise the overall energy consumption of the process and reduce the operational cost.
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33.
  • Khan, Aisha, et al. (författare)
  • Epidemiological and Pathological Characteristics of Cutaneous Leishmaniasis from Baluchistan Province of Pakistan
  • 2021
  • Ingår i: Parasitology. - : Cambridge University Press. - 0031-1820 .- 1469-8161. ; 148:5, s. 591-597
  • Tidskriftsartikel (refereegranskat)abstract
    • Cutaneous Leishmaniasis (CL) is considered a neglected tropical disease which in Pakistan can now be considered as growing public health problem. The exact figures on the magnitude of disease are lacking both at national and regional level and only a few health centers are available for diagnosis of CL. The present study was designed to identify the epidemiology of CL infection from August 2018 to December 2019 and to assess clinical aspects of CL in Baluchistan Province of Pakistan. A total of 4072 clinically suspected CL cases were analysed statistically. The highest number of CL cases were reported in May, followed by April, January and then July, February, and June and lowest number of cases were observed in March and November. The highest prevalence rate was found in males where 38% of reported cases were aged 0-9 years. The majority (24.4%) of lesions were found on the hands followed by the face in which cheeks, ears and nose were the effected organs. About 50% of the participants have single lesion while 14% of the participants had two and nearly 3% of the participants have six lesions. The atypical clinical presentations were observed in Baluchistan and common unusual presentations were lupus erythematosus. The study findings suggest that more epidemiological studies and health education campaigns are needed for the population awareness regarding CL in Baluchistan. It is recommended that risk factors should be evaluated to establish the control and management strategies to prevent disease at individual and community level. 
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34.
  • Majeed, Khaliq, et al. (författare)
  • Shuffled Complex Evolution-Based Performance Enhancement and Analysis of Cascade Liquefaction Process for Large-Scale LNG Production
  • 2020
  • Ingår i: Energies. - : MDPI. - 1996-1073. ; 13:10
  • 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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35.
  • Micah, Angela E., et al. (författare)
  • Tracking development assistance for health and for COVID-19 : a review of development assistance, government, out-of-pocket, and other private spending on health for 204 countries and territories, 1990-2050
  • 2021
  • Ingår i: The Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 398:10308, s. 1317-1343
  • Forskningsöversikt (refereegranskat)abstract
    • Background The rapid spread of COVID-19 renewed the focus on how health systems across the globe are financed, especially during public health emergencies. Development assistance is an important source of health financing in many low-income countries, yet little is known about how much of this funding was disbursed for COVID-19. We aimed to put development assistance for health for COVID-19 in the context of broader trends in global health financing, and to estimate total health spending from 1995 to 2050 and development assistance for COVID-19 in 2020. Methods We estimated domestic health spending and development assistance for health to generate total health-sector spending estimates for 204 countries and territories. We leveraged data from the WHO Global Health Expenditure Database to produce estimates of domestic health spending. To generate estimates for development assistance for health, we relied on project-level disbursement data from the major international development agencies' online databases and annual financial statements and reports for information on income sources. To adjust our estimates for 2020 to include disbursements related to COVID-19, we extracted project data on commitments and disbursements from a broader set of databases (because not all of the data sources used to estimate the historical series extend to 2020), including the UN Office of Humanitarian Assistance Financial Tracking Service and the International Aid Transparency Initiative. We reported all the historic and future spending estimates in inflation-adjusted 2020 US$, 2020 US$ per capita, purchasing-power parity-adjusted US$ per capita, and as a proportion of gross domestic product. We used various models to generate future health spending to 2050. Findings In 2019, health spending globally reached $8. 8 trillion (95% uncertainty interval [UI] 8.7-8.8) or $1132 (1119-1143) per person. Spending on health varied within and across income groups and geographical regions. Of this total, $40.4 billion (0.5%, 95% UI 0.5-0.5) was development assistance for health provided to low-income and middle-income countries, which made up 24.6% (UI 24.0-25.1) of total spending in low-income countries. We estimate that $54.8 billion in development assistance for health was disbursed in 2020. Of this, $13.7 billion was targeted toward the COVID-19 health response. $12.3 billion was newly committed and $1.4 billion was repurposed from existing health projects. $3.1 billion (22.4%) of the funds focused on country-level coordination and $2.4 billion (17.9%) was for supply chain and logistics. Only $714.4 million (7.7%) of COVID-19 development assistance for health went to Latin America, despite this region reporting 34.3% of total recorded COVID-19 deaths in low-income or middle-income countries in 2020. Spending on health is expected to rise to $1519 (1448-1591) per person in 2050, although spending across countries is expected to remain varied. Interpretation Global health spending is expected to continue to grow, but remain unequally distributed between countries. We estimate that development organisations substantially increased the amount of development assistance for health provided in 2020. Continued efforts are needed to raise sufficient resources to mitigate the pandemic for the most vulnerable, and to help curtail the pandemic for all. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.
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36.
  • Naqvi, Muhammad, et al. (författare)
  • 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
  • Ingår i: International journal of hydrogen energy. - : Elsevier. - 0360-3199 .- 1879-3487. ; 41:25, s. 10608-10618
  • 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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37.
  • Naqvi, Muhammad, et al. (författare)
  • Polygeneration system integrated with small non-wood pulp mills for substitute natural gas production
  • 2018
  • Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 224, s. 636-646
  • Tidskriftsartikel (refereegranskat)abstract
    • This study aims to examine the potential substitute natural gas (SNG) production by integrating black liquor gasification (BLG) island with a small wheat straw-based non-wood pulp mills (NPM), which do not employ the black liquor recovery cycle. For such integration, it is important to first build knowledge on expected improvements in an overall integrated non-wood pulp mill energy system using the key performance indicators. O2-blown circulating fluidized bed (CFB) gasification with direct causticization is integrated with a reference small NPM to evaluate the overall performance. A detailed economic analysis is performed together with a sensitivity analysis based on variations in the rate of return due to varying biomass price, total capital investment, and natural gas prices. The quantitive results showed considerable SNG production but significantly reduced electricity production. There is a substantial CO2 abatement potential combining CO2 capture and CO2 mitigation from SNG use replacing compressed natural gas (CNG) or gasoline. The economic performance through sensitivity analysis reflects significant dependency on both substitute natural gas production and natural gas market price. Furthermore, the solutions to address the challenges and barriers for the successful commercial implementation of BLG based polygeneration system at small NPMs are discussed. The system performance and discussion on the real application of integrated system presented in this article form a vital literature source for future use by large number of small non-wood pulp industries.
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38.
  • Naqvi, Muhammad Raza, 1983-, et al. (författare)
  • Off-grid electricity generation using mixed biomass compost: : A scenario-based study with sensitivity analysis
  • 2017
  • Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 201, s. 363-370
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of the study is to investigate the viability of waste gasification based off-grid electricity gener- ation utilizing mixed biomass composts (mixture of rice hulls with cow/poultry manure compost). The economic viability is studied on the different scenarios with considerations of (1) levels of electricity demand and utilization, (2) costs of variable biomass mix, (3) combined domestic and cottage industry business model, and (4) influence of governmental investments. The levelized cost of electricity (LCOE) is used as an indicator to measure the competitiveness of gasification based off-grid electricity genera- tion. The plant loading and the capacity factor have been used to assess the impacts of different scenarios. A sensitivity analysis of key parameters based on variations in annual operational hours, plant efficiency, plant cost and biomass supply cost is conducted. Based on levels of electricity demand and utilization, the LCOE ranged between 40 US cents/kW h and 29 US cents/kW h based on the plant loading and the capac- ity factor. The business revenue would not change considerably despite better plant utilization and reduced levelized cost of electricity if all the consumers, both basic or medium, are charged with the flat tariff. The part load operation will be costly despite considerably low capital investment per kW in com- parison with PV or solar based plants. There is a large potential of off-grid electricity generation but the estimated off-grid electricity price is found to be higher in all scenarios than average grid-based electric- ity tariff. Moreover, the challenges for the implementation of the real off-grid electricity generation plant are discussed. 
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39.
  •  
40.
  • Naqvi, Muhammad, et al. (författare)
  • Waste Biomass Gasification Based off-grid Electricity Generation : A Case Study in Pakistan
  • 2016
  • Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 103, s. 406-412, s. 406-412
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective is to investigate the waste gasification based off-grid electricity generation in developing countries like Pakistan utilizing mixed biomass composts (mixture of agricultural wastes including rice hulls and wheat straw with cow/poultry manure compost). Different scenarios are compared; (1) levels of electricity demand and utilization, (2) costs for variable biomass mix, (3) combined domestic and cottage industry business model. The levelized cost of electricity (LCOE) is used as an indicator to measure the competitiveness of off-grid electricity generation. There is a large potential of off-grid electricity generation. However, the estimated off-grid electricity price is found to be higher in all scenarios than average governmental electricity tariff.
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41.
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42.
  • Naqvi, S. R., et al. (författare)
  • Catalytic Consequences of Micropore Topology on Biomass Pyrolysis Vapors over Shape Selective Zeolites
  • 2017
  • Ingår i: Energy Procedia. - : Elsevier Ltd. - 1876-6102. ; , s. 557-561, s. 557-561
  • Konferensbidrag (refereegranskat)abstract
    • Research on utilization of abundant rice residue for valuable bioenergy products is still not explored completely. A simple, robust, cheap and one step fast pyrolysis reactor is still a key demand for production of bioenergy products, i.e. high quality bio-oil and bio char. Bio-oil produced from fast pyrolysis has poor quality (e.g. acidic and highly oxygenated). Catalytic fast pyrolysis using zeolites in the fast pyrolysis process effectively reduce the oxygen content (no H2 required). In this paper, zeolites having a variety of pore size and shape (small pore: SAPO-34 (0.56), Ferriertite (20), medium pore: ZSM-5 (23), MCM-22 (20), ITQ-2 (20) and large pore zeolite Mordenite (20) were tested in a drop type fixed-bed pyrolyzer. The catalytic deoxygenation is conducted at 450°C at the catalyst/biomass ratio of 0.1. Zeolite catalysts, its pore size and shape could influence largely on deoxygenation. Small pore zeolites did not produce aromatics while medium pore zeolites formed higher amount of aromatics. ZSM-5 and ITQ-2 zeolites were especially efficient for the higher deoxygenation of biomass pyrolysis vapors due to better pore dimension and higher acidity. © 2017 The Authors.
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43.
  • Naqvi, Salman Raza, et al. (författare)
  • Catalytic fast pyrolysis of rice husk : Influence of commercial and synthesized microporous zeolites on deoxygenation of biomass pyrolysis vapors
  • 2018
  • Ingår i: International Journal of Energy Research. - : Wiley-Blackwell. - 0363-907X .- 1099-114X. ; 42:3, s. 1352-1362
  • Tidskriftsartikel (refereegranskat)abstract
    • Research on utilization of abundant rice residue for valuable bioenergy products is still not explored completely. A simple, robust, cheap, and one-step fast pyrolysis reactor is still a key demand for production of bioenergy products, ie, high quality bio-oil and biochar. Bio-oil extracted from fast pyrolysis does not have adequate quality (eg, acidic and highly oxygenated). Catalytic fast pyrolysis using zeolites in the fast pyrolysis process effectively reduces the oxygen content (no H-2 required). In this paper, the zeolites with different pore sizes and shapes (small pore, SAPO-34 (0.56) and ferrierite (30); medium pore, ZSM-5 (30), MCM-22 (30), and ITQ-2 (30); and large pore zeolite, mordenite (30)) were tested in a drop-type fixed-bed pyrolyzer. Catalytic deoxygenation is conducted at 450 degrees C at the catalyst/biomass ratio of 0.1. Zeolite catalysts, its pore size and shape, could influence largely on deoxygenation. It was found that the small pore zeolites did not produce aromatics as compared to higher amount of aromatics formed in case of medium pore zeolites. ZSM-5 and ITQ-2 zeolites were especially efficient for the higher deoxygenation of biomass pyrolysis vapors due to better pore dimension and higher acidity.
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44.
  • Naqvi, Salman Raza, et al. (författare)
  • Catalytic Pyrolysis Of Botryococcus Braunii (microalgae) Over Layered and Delaminated Zeolites For Aromatic Hydrocarbon Production
  • 2017
  • Ingår i: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY. - : ELSEVIER SCIENCE BV. ; , s. 381-385
  • Konferensbidrag (refereegranskat)abstract
    • Botryococcus braunii (B. Braunii) is considered as due to its high capability of large aromatic contents, prominent green microalgae as a renewable energy resource. The aim and novelty of this work is to exploit the pyrolysis characteristics of microalgae with layered and delaminated zeolites using Py-GC/MS. No catalyst and catalytic pyrolysis was compared to evaluate product components formed. Further, the catalytic pyrolysis of botryococcus braunii was carried out in the presence of two zeolites with different pore topology and acidity. The results from non-catalytic microalgae pyrolysis were compared to catalytic pyrolysis together with different catalysts to biomass ratios for aromatic hydrocarbons production. Py-GC/MS results showed the aromatic hydrocarbon production (area%) was significantly improved from zeolite catalytic pyrolysis than non-catalytic pyrolysis. The increase in catalyst to biomass ratio (3:1 and 5:1) resulted in higher aromatic hydrocarbon production. As the catalyst to biomass ratio increased, it is observed that aromatic hydrocarbon content increased as compared to low catalyst to biomass ratio. In addition, ITQ-2 zeolite generated higher aromatic hydrocarbons. This might be due to better pore structure and acidity of delaminated structure as compared to layered structure. This delaminated topology enhances the reactant diffusion and reduces the secondary cracking.
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45.
  • Naqvi, Salman Raza, et al. (författare)
  • Circular Economy Approach to Address the Industrial Solid Waste Management
  • 2022
  • Ingår i: Handbook of Solid Waste Management. - Singapore : Springer. - 9789811642296 - 9789811642302 ; , s. 421-440
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
    • Industrial activities continuously generate diverse characteristics of various types of wastes. Industrial wastes varied from various process residues, wastes from pollution, or decontamination from operations and materials resulting from activities for contaminated soil remediation, ashes, oil, acidic wastes, plastic, paper, wood, fiber, rubber, metals, and glass. The circular tools indicate a restorative and regenerative system in which the streams of materials and products take place in a circular way. Considering social pressures, major industrial enterprises perceived the need for readjusting their production chains according to circular chains, which are more sustainable and consider the generated waste. This study aims to present the factors for sustainable waste management in major industrial enterprises based on the circular economy approach. The available data of a waste company is considered, and the model of circular economy such as fault tree analysis is applied to figure out the implementation of a circular process to industrial waste, especially those of lower value that have greater difficulties in being processed. The last section will propose a framework, opportunities, challenges, and trade-offs promoting circulatory industrial waste management.
  •  
46.
  • Naqvi, Salman Raza, et al. (författare)
  • Impact of layered and delaminated zeolites on catalytic fast pyrolysis of microalgae using fixed-bed reactor and Py-GC/MS
  • 2021
  • Ingår i: Journal of Analytical and Applied Pyrolysis. - : Elsevier. - 0165-2370 .- 1873-250X. ; 155
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this work is to exploit the pyrolysis characteristics of microalgae Botryococcus braunii (BB) with a medium pore framework zeolite (MCM-22) and its delaminated counterpart with a higher external surface area zeolite (ITQ-2) using pyrolysis-gas-chromatography-mass-spectrometry (Py-GC/MS) and a fixed-bed reactor. The study evaluates the effect of synthesized zeolites that possess different pore size, shape and acidity on promoting deoxygenation reactions and producing aromatic compounds during the pyrolysis of microalgae. Further, the role of the shape of zeolites (layered & delaminated) for carbohydrate, protein and lipid-derived compounds formation is discussed. The Py-GC/MS results showed that the aromatic compounds (area%) was significantly higher (35.17 %) for delaminated & (28.76 %) for layered zeolites than non-catalytic pyrolysis (17.85 %) at the catalyst/biomass ratio of 10.1. The increase in catalyst/biomass ratio from 3 to 10 at 550 °C has increased the aromatics (90.66 % for ITQ-2 & 75.25 %) for MCM-22 zeolites. In addition, ITQ-2 zeolite produced 20.47 % higher aromatics than MCM-22 zeolites which is attributed to the thinner delaminated structure of ITQ-2 that makes reactants more accessible to the catalytic site and accelerate the deoxygenation reactions.
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47.
  • Naqvi, Salman Raza, et al. (författare)
  • Pyrolysis of high-ash sewage sludge : Thermo-kinetic study using TGA and artificial neural networks
  • 2018
  • Ingår i: Fuel. - Oxon, UK : Elsevier Ltd. - 0016-2361 .- 1873-7153. ; 233, s. 529-538
  • Tidskriftsartikel (refereegranskat)abstract
    • Pyrolysis of high-ash sewage sludge (HASS) is a considered as an effective method and a promising way for energy production from solid waste of wastewater treatment facilities. The main purpose of this work is to build knowledge on pyrolysis mechanisms, kinetics, thermos-gravimetric analysis of high-ash (44.6%) sewage sludge using model-free methods & results validation with artificial neural network (ANN). TG-DTG curves at 5,10 and 20 °C/min showed the pyrolysis zone was divided into three zone. In kinetics, E values of models ranges are; Friedman (10.6–306.2 kJ/mol), FWO (45.6–231.7 kJ/mol), KAS (41.4–232.1 kJ/mol) and Popescu (44.1–241.1 kJ/mol) respectively. ΔH and ΔG values predicted by OFW, KAS and Popescu method are in good agreement and ranged from (41–236 kJ/mol) and 53–304 kJ/mol, respectively. Negative value of ΔS showed the non-spontaneity of the process. An artificial neural network (ANN) model of 2 * 5 * 1 architecture was employed to predict the thermal decomposition of high-ash sewage sludge, showed a good agreement between the experimental values and predicted values (R2 ⩾ 0.999) are much closer to 1. Overall, the study reflected the significance of ANN model that could be used as an effective fit model to the thermogravimetric experimental data. © 2018 Elsevier Ltd
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48.
  • Naqvi, Salman Raza, et al. (författare)
  • The role of zeolite structure and acidity in catalytic deoxygenation of biomass pyrolysis vapors
  • 2015
  • Ingår i: CLEAN, EFFICIENT AND AFFORDABLE ENERGY FOR A SUSTAINABLE FUTURE. - : Elsevier. ; 75, s. 793-800
  • Konferensbidrag (refereegranskat)abstract
    • Catalytic upgrading of paddy husk was performed over 10-MR zeolites (MCM-22, ITQ-2 and ZSM-5) in a drop type fixed-bed reactor. This work investigated the role of structure and acidity of zeolites on pyrolysis-oil yield and degree of deoxygenation. Catalytic pyrolysis experiments were carried out at the catalyst/biomass ratio (0.05 -0.5) at temperature of 450 degrees C. The oil yield decreased by using catalyst and this decrease oil yield is attributed to catalytic cracking of bio-oil vapor on the catalyst. The route for deoxygenation of pyrolysis vapors was identified to be dehydration, decarboxylation and decarboxylation. ITQ-2 showed high degree of deoxygenation as compare to MCM-22 which is due to more accessible external active sites of ITQ-2. The organics yield in pyrolysis oil was highest with ZSM-5 in comparison with other zeolites. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
  •  
49.
  • Nizami, Abdul-Sattar, et al. (författare)
  • Energy, economic and environmental savings by waste recycling : A case study of Madinah City
  • 2017
  • Ingår i: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON APPLIED ENERGY. - : Elsevier. ; 142, s. 910-915
  • Konferensbidrag (refereegranskat)abstract
    • In the Kingdom of Saudi Arabia (KSA), millions of worshippers come from across the globe to perform religious rituals of Pilgrimage (Hajj) and Umrah. Madinah-tul-Munawara is one of the holiest city, where pilgrims come after performing rituals in Makkah. In this city, most of the collected municipal solid waste (MSW) is disposed of in the landfills after a partial recycling of paper, cardboard, and metals (similar to 10-20% of total MSW). The Saudi's government has recently launched a new policy of Vision 2030, which outlined the safeguard of local environment through increased efficiency of waste recycling and management, pollution prevention strategies and generating renewable energy from indigenous sources, including the waste. Currently, the recycling practices in KSA are mainly regulated by an informal sector through waste pickers or waste scavengers. This has led to the need of recycling schemes, especially in the holiest cities of Makkah and Madinah through a public-private partnership (PPP). Huge amounts of energy can be conserved, that would otherwise be spent on raw material extraction, transportation, and manufacturing of materials, through recycling into the same materials. Around 10,009 TJ of energy can be saved through recycling of 24.21% of MSW in Madinah city, including glass, metals, aluminum, cardboard, and paper. It is estimated that around 10,200 tons of methane (CH4) emissions and 254,600 Mt center dot CO2 eq. of global warming potential (GWP) can also be saved. In addition, carbon credit revenue of US $5.92 million, and landfill diversion worth of US $32.78 million can be achieved with a net revenue of US $49.01 million every year only by recycling 24.21% of MSW in Madinah city. The waste recycling doesn't require high technical skills and labor, and complicated technologies for large-scale implementation, and therefore, can be implemented easily in the holiest cities of Makkah and Madinah to achieve multiple economic and environmental benefits. (C) 2017 The Authors. Published by Elsevier Ltd.
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50.
  • Nizami, Abdul-Sattar, et al. (författare)
  • Waste biorefineries : enabling circular economies in developing countries
  • 2017
  • Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 241, s. 1101-1117
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper aims to examine the potential of waste biorefineries in developing countries as a solution to current waste disposal problems and as facilities to produce fuels, power, heat, and value-added products. The waste in developing countries represents a significant source of biomass, recycled materials, chemicals, energy, and revenue if wisely managed and used as a potential feedstock in various biorefinery technologies such as fermentation, anaerobic digestion (AD), pyrolysis, incineration, and gasification. However, the selection or integration of biorefinery technologies in any developing country should be based on its waste characterization. Waste biorefineries if developed in developing countries could provide energy generation, land savings, new businesses and consequent job creation, savings of landfills costs, GHG emissions reduction, and savings of natural resources of land, soil, and groundwater. The challenges in route to successful implementation of biorefinery concept in the developing countries are also presented using life cycle assessment (LCA) studies. (C) 2017 Elsevier Ltd. All rights reserved.
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