| 1. |
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| 2. |
- Andersson, Viktor, 1983, et al.
(författare)
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Alkali interactions with a calcium manganite oxygen carrier used in chemical looping combustion
- 2022
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Ingår i: Fuel Processing Technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 227
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Tidskriftsartikel (refereegranskat)abstract
- Chemical-Looping Combustion (CLC) of biofuels is a promising technology for cost-efficient CO2 separation and can lead to negative CO2 emissions when combined with carbon capture and storage. A potential challenge in developing CLC technology is the effects of alkali metal-containing compounds released during fuel conversion. This study investigates the interactions between alkali and an oxygen carrier (OC), CaMn0.775Ti0.125Mg0.1O3-δ, to better understand the fate of alkali in CLC. A laboratory-scale fluidized bed reactor is operated at 800–900 °C in oxidizing, reducing and inert atmospheres to mimic CLC conditions. Alkali is fed to the reactor as aerosol KCl particles, and alkali in the exhaust is measured online with a surface ionization detector. The alkali concentration changes with gas environment, temperature, and alkali loading, and the concentration profile has excellent reproducibility over repeated redox cycles. Alkali-OC interactions are dominated by alkali uptake under most conditions, except for a release during OC reduction. Uptake is significant during stable reducing conditions, and is limited under oxidizing conditions. The total uptake during a redox cycle is favored by a high alkali loading, while the influence of temperature is weak. The implications for the understanding of alkali behavior in CLC and further development are discussed.
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| 3. |
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| 4. |
- Ebrahimi, P., et al.
(författare)
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Systematic Optimization of Boron Diffusion for Solar Cell Emitters
- 2017
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Ingår i: Journal of Electronic Materials. - : Springer. - 0361-5235 .- 1543-186X. ; 46:7, s. 4236-4241
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Tidskriftsartikel (refereegranskat)abstract
- To achieve p-n junctions for n-type solar cells, we have studied BBr3 diffusion in an open tube furnace, varying parameters of the BBr3 diffusion process such as temperature, gas flows, and duration of individual process steps, i.e., predeposition and drive-in. Then, output parameters such as carrier lifetime, sheet resistance, and diffusion profile were measured and statistically analyzed to optimize the emitter characteristics. Statistical analysis (factorial design) was finally employed to systematically explore the effects of the set of input variables on the outputs. The effect of the interactions between inputs was also evaluated for each output, quantified using a two-level factorial method. Temperature and BBr3 flow were found to have the most significant effect on different outputs such as carrier lifetime, junction depth, sheet resistance, and final surface concentration.
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| 5. |
- Gogolev, Ivan, 1984, et al.
(författare)
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Commissioning, performance benchmarking, and investigation of alkali emissions in a 10 kWth solid fuel chemical looping combustion pilot
- 2021
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 287
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Tidskriftsartikel (refereegranskat)abstract
- Chemical looping combustion of biomass-sourced fuels (bio-CLC) is a novel bio-energy with carbon capture and storage (BECCS) technology for power and heat generation with net negative CO2 emissions. In this study, a new 10 kWth CLC pilot designed for high-volatiles biomass fuels was commissioned with ilmenite oxygen carrier and five different biomass fuels of varying volatile and alkali content fractions. The system was tested for its ability to convert high and low volatile content biomass, while achieving high carbon capture efficiency. The new pilot achieved carbon capture close to 100% for high-volatiles biomass, and >94% for low-volatiles biomass char fuels. Furthermore, due to the implementation of a volatiles distributor, the new pilot demonstrated an improvement of up to 10 percentage points of gas conversion efficiency for high-volatiles biomass vs. the previous generation reactor. Gaseous alkali emissions were measured with a surface ionization detection system. Flue gas alkali release levels were found to rise with higher fuel alkali content. Alkali emissions were found to be approximately similar in the AR and the FR for all but the straw pellet mixture fuel (highest alkali content fuel). For the straw pellet mixture, gaseous alkali release levels in the AR were up to seven times higher than those of the FR. In all cases, over 96% of the fuel's alkalis were absorbed by the ilmenite bed material. Ilmenite's strong alkali absorption characteristics were concluded to be the key determinant of gas-phase release of biomass alkali in the conducted experiments.
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| 6. |
- Gogolev, Ivan, 1984, et al.
(författare)
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Effects of Temperature, Operation Mode, and Steam Concentration on Alkali Release in Chemical Looping Conversion of Biomass-Experimental Investigation in a 10 kWthPilot
- 2022
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Ingår i: Energy & Fuels. - : American Chemical Society. - 0887-0624 .- 1520-5029. ; 36:17, s. 9551-9570
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Tidskriftsartikel (refereegranskat)abstract
- Alkali release was studied in a 10 kWthchemical looping pilot operated with a Linz-Donawitz (LD) slag oxygen carrier (OC) and three biomass fuels. Experiments were performed at three temperatures and in three operation modes: chemical looping combustion (CLC), chemical looping gasification (CLG), and oxygen-carrier-aided combustion (OCAC). Gas-phase alkali release was measured with a surface ionization detector (SID). Fuel reactor (FR) gas-phase alkali emissions increased with the temperature. This occurred as a result of increased evaporation of KCl and enhanced decomposition of alkali salts during char conversion. Air reactor (AR) alkali emissions were lower than in the FR and independent of the operating temperature. In comparison of operating modes, CLC and CLG modes resulted in similar gas-phase alkali emissions due to the similar extent of char conversion. In contrast, operation of the reactor system in OCAC mode resulted in significantly lower levels of gas-phase alkalis. The difference in alkali emission was attributed to the steam-rich atmosphere of CLC. The effect of steam was further investigated in CLC and OCAC tests. Lowering steam concentrations in CLC operation resulted in lower gas-phase alkali emissions, while introducing steam to the FR during OCAC operation resulted in higher alkali emissions. It was concluded that steam likely enhances gas-phase K release through a reaction of K2CO3within the fuel char with steam to produce KOH(g). Solid sampling and analysis for K content was used along with SID measurements to develop a K mass balance for the reactor system. Mass balance results for the straw pellet fuel tests showed that LD slag OC absorbs approximately 15-51% of fuel K, 2.2% of fuel K is released to the gas phase, and up to 3.4% of fuel K is captured in the AR fly ash. The residual 40-80% of fuel K was determined to leave the FR as K-rich fly ash.
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| 7. |
- Hedayati, Ali, 1984, et al.
(författare)
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Experimental evaluation of manganese ores for chemical looping conversion of synthetic biomass volatiles in a 300 W reactor system
- 2021
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Ingår i: Journal of Environmental Chemical Engineering. - : Elsevier BV. - 2213-3437 .- 2213-2929. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- Two manganese ores with different iron content were investigated as oxygen carriers for chemical looping conversion of simulated biomass volatiles. The aim was to study the performance of the oxygen carriers with regards to combustion and potential use for chemical-looping gasification of wood-based biomass. The oxygen carriers were studied in a 300 W chemical-looping reactor system with circulation of oxygen carriers between the fluidized air and fuel reactors. The temperature was 850-900 °C and the fuel flow rates were 0.6-3 Lmin-1. The Mn ore with higher iron content showed significant oxygen release at 900 °C under inert conditions, as well as full conversion of CO, H2 and methane at low fuel flow. The other Mn ore showed little methane conversion and poorer conversion of the other gases when compared at similar fuel flows. However, the gas composition attained was rather similar if compared for a similar overall gas conversion. Nonetheless, a slightly higher syngas fraction and H2 to CO ratio in the product stream was obtained with the Mn ore with lower iron content. In all cases the syngas fraction in the product gas increased with temperature and fuel flow. The formation of fines (attrition rate), particle size distribution, and the bulk density of the oxygen carriers were measured to evaluate their mechanical properties during chemical looping of biomass volatiles.
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| 8. |
- Hedayati, Ali, 1984, et al.
(författare)
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Thermochemical conversion of biomass volatiles via chemical looping: Comparison of ilmenite and steel converter waste materials as oxygen carriers
- 2022
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 313
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Tidskriftsartikel (refereegranskat)abstract
- Two oxygen carriers were tested with respect to chemical looping combustion (CLC) and chemical looping gasification (CLG). Ilmenite, a natural ore composed mainly of iron–titanium oxide, and LD Slag, an iron-based industrial waste, were investigated at 850 and 900 °C in a continuous operation in a 0.3 kW chemical-looping reactor system using synthetic biomass volatiles as fuel. CLC and CLG conditions were simulated in the fuel reactor by changing the fuel flow rates. In the case of ilmenite the syngas yield and methane conversion increased with fuel flow rate. Consequently, the syngas to hydrocarbon ratio was higher for ilmenite. Methane conversion improved for both tested oxygen carriers with increasing the operating temperature. Oxygen release was observed in the case of LD Slag. The H2/CO ratio was between 0.7 and 0.8 for both oxygen carriers at the higher fuel flows. With respect to CLC, ilmenite showed higher gas conversion than LD slag. Analysis of the particles revealed that ilmenite possessed better mechanical properties and formed less dust compared to LD Slag during the continuous operation with fuel.
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| 9. |
- Hildor, Fredrik, 1992, et al.
(författare)
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Tar characteristics generated from a 10 kW th chemical-looping biomass gasifier using steel converter slag as an oxygen carrier
- 2023
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 331
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Tidskriftsartikel (refereegranskat)abstract
- Tar management is one of the key components to achieve high energy efficiency and low operational costs connected to thermal gasification of biomass. Tars contain a significant amount of energy, and unconverted tars result in energy efficiency losses. Also, heavy tars can condense downstream processes, resulting in increased maintenance. Dual fluidized beds for indirect gasification operated with active bed material can be a way to better convert and control the tar generated in the process. Using an active material to transport oxygen in an indirect dual reactor gasification setup is referred to as chemical-looping gasification (CLG). A higher oxidative environment in the gas phase, in addition to possible catalytic sites, could mean lower yields in comparison to normal indirect gasification. This paper investigates the effect of using Steel converter slag (LD slag), a byproduct of steel manufacturing, as an oxygen-carrying bed material on tar species generated in a 10 kWth dual fluidized bed biomass gasifier. The results are compared to the benchmark oxygen carrier ilmenite and conventional silica sand. Three different solid biofuels were used in the reactor system: steam exploded pellets, pine forest residue and straw. Tar was absorbed from the raw syngas using a Solid Phase Adsorption (SPA) column and was analyzed using GC-FID. Bench-scale experiments were also performed to investigate benzene conversion of LD slag and ilmenite at different oxidation levels. The findings of this study suggest that oxygen carriers can be used to decrease the tars generated in a dual fluidized bed system during gasification. Phases in LD slag possess catalytic properties, resulting in a decreased ratio of heavy tar components compared to both ilmenite and sand. Temperature and fuel load showed a significant effect on the tar generation compared to the circulation and steam ratio in this reactor system. Increased temperature generated lower tar yields and lower ratios of heavy tar components for LD slag in contrast to sand.
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| 10. |
- Karami, Davood, et al.
(författare)
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Preparation of Novel Oxygen Carriers Supported by Ti, Zr-Shelled γ-Alumina for Chemical Looping Combustion of Methane
- 2020
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Ingår i: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 1520-5045 .- 0888-5885. ; 59:7, s. 3221-3228
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Tidskriftsartikel (refereegranskat)abstract
- Highly stabilized mesoporous core-shell-structured oxygen carriers (OCs) were fabricated by a repetitive coating process of alumina supports using the mesopore-forming surfactant assembly method. The wet coating strategy, along with the sol-gel process, was used for the synthesis of mesoporous material-shelled OCs with various shell compositions (i.e., zirconia, titania). The cyclic performance of the synthesized OCs during chemical looping combustion (CLC) was investigated in a thermogravimetric analyzer (TGA). The mesoporous-shelled OCs demonstrated significantly better performance compared to the OCs without mesoporous shells. The synthesized OCs with a mesoporous zirconia/titania shell reveal a unique oxygen capacity of 100% based on active metal oxide for supported NiO and Fe2O3. Also, the synthesized OCs showed no activity loss after 10 cycles. This was attributed to the exceptional core-shell coating strategy, in which the thermally stable mesoporous Zr/Ti layers prevent the sintering and over-reaction of the active metal oxide crystals with the alumina support.
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| 11. |
- Kermaniha, M., et al.
(författare)
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Systematic optimization of phosphorous diffusion for solar cell application
- 2016
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Ingår i: Journal of materials science. Materials in electronics. - : Springer-Verlag New York. - 0957-4522 .- 1573-482X. ; 27:12, s. 13086-13092
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Tidskriftsartikel (refereegranskat)abstract
- Fossil fuel storage is running low and scientists around the globe are involved in a big search for an optimized substitute. Photovoltaic is one of the most likely alternatives to solve this issue and replace the fossil fuels. Among all types of cells, silicon solar cells are the most economical ones to produce affordable energy. In this paper, a systematic study was done on the diffusion of phosphorous in multi-crystalline silicon during solar cell emitter formation. All parameters involved in the conversion of a multi-crystalline p-type silicon to a p-n junction were analyzed quantitatively. This systematic approach predicts the effect of inputs on the outputs which decreases the number of the trail runs. The analysis result indicate, that raising the diffusion temperature from 830 to 880 A degrees C decreases the sheet resistance by -100 Omega/sq, and increasing POCl3 flow from 300 to 500 SCCM has an effect of -21 Omega/sq.
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| 12. |
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| 13. |
- Mei, Daofeng, 1986, et al.
(författare)
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Modelling of gas conversion with an analytical reactor model for biomass chemical looping combustion (bio-CLC) of solid fuels
- 2022
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 433
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Tidskriftsartikel (refereegranskat)abstract
- Manganese ores are promising oxygen carriers for chemical looping combustion (CLC), due to their high reactivity with combustible gases. In this work, a manganese ore called EB (Elwaleed B, originating from Egypt) is studied for its reaction rate with CH4, CO and H2 and the data are used in an analytically solved reactor model. The reactivity of fresh and three used EB samples from previous operation in a 10 kWth pilot was examined in a batch fluidized bed reactor with CH4 and syngas (50%CO + 50%H2). In comparison with other manganese ores, the EB ore has a lower rate of reaction with CH4, while showing a significantly higher reactivity with syngas. Nevertheless, this manganese ore always presents a better conversion of CH4 and syngas than the benchmark ilmenite. Mass-based reaction rate constants were obtained using a pseudo first-order reaction mechanism: 1.1·10-4 m3/(kg·s) for CH4, 6.6·10-3 m3/(kg·s) for CO and 7.5·10-3 m3/(kg·s) for H2. These rate constants were used in an analytical reactor model to further investigate results from previous operation in the 10 kWth unit. According to the analytical model, in the 10 kWth operation, 98% of the char in the biomass fuels was gasified before leaving the fuel reactor, while the char gasification products (CO and H2) have a 90% contact efficiency with the bed material. On the contrary, the volatiles have a much lower contact efficiency with the oxygen carrier bed, i.e. 20%, leading to low conversion of volatiles released. Thus, the results emphasize the importance of improving the contact between volatiles and bed material in order to promote combustion performance in the CLC process.
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| 14. |
- Mei, Daofeng, 1986, et al.
(författare)
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Reactivity and lifetime assessment of an oxygen releasable manganese ore with biomass fuels in a 10 kW th pilot rig for chemical looping combustion
- 2021
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Ingår i: Fuel Processing Technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 215
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Tidskriftsartikel (refereegranskat)abstract
- Finding a suitable oxygen carrier is crucial for the development of Chemical Looping Combustion (CLC). A new manganese ore was tested with different biomass fuels in a recently commissioned 10 kWth unit. The ore maintains the capability of generating O2 gas in N2 after continuous operations with the fuels, however, the concentration was relatively low within 0.45–1.0 vol% at 820 to 975 °C. Influence of temperature, solids circulation and fuel power was examined for different fuels. Temperature increase enhances the carbon capture and reduces the oxygen demand, while the solids circulation and fuel power should be carefully controlled. Using biomass char the oxygen demand can be lowered to 2.6% while the carbon capture was close to 99%. The manganese ore showed a higher reactivity than the often-used ilmenite. Thus, a decrease of 8–10% in oxygen demand was achieved by using the manganese ore in comparison to ilmenite. During the 42 h of hot operation, defluidisation was not observed. Based on the analysis of the 35 fine samples collected, the initial attrition after first hours of operation was high, but gradually decreased to a relatively stable value of 0.27 and 0.12 wt%/h for hot and fuel operations, respectively, corresponding a lifetime of 370–830 h.
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| 15. |
- Momeni, H. R., et al.
(författare)
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Apoptosis in cultured spinal cord slices of neonatal mouse
- 2008
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Ingår i: Iranian Journal of Science and Technology Transaction A: Science. - 1028-6276. ; 32:A2, s. 109-116
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Tidskriftsartikel (refereegranskat)abstract
- Organotypic spinal cord slices from neonatal mammals could be a powerful model for evaluation of cell survival but also cell death mechanisms. The aim of this study was to establish an in vitro model for investigating cell survival and mechanism involved in cell death in neonatal spinal cord slices. The spinal cord was sliced and incubated into culture medium. The MTT assay was carried out to assess the viability of the slices and fluorescent staining was used to study morphological features of apoptosis, where as nucleosomal DNA fragmentation was detected using agarose gel electrophoresis. The results of the present study demonstrated that the slices could be maintained in culture up to 14 days. Both neurons and glial cells died by apoptosis and application of a general caspase inhibitor neither affected slice survival nor nucleosomal DNA fragmentation after 24 h in culture. In addition, the inhibitor failed to block apoptosis in neurons and glial cells in the cultured slices. Our results suggest that in the cultured slices, apoptosis is the main reason for neuron and glial cell death, which occurs by a caspase-independent mechanism.
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| 16. |
- Purnomo, Victor, 1992, et al.
(författare)
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Effect of the Mass Conversion Degree of an Oxygen Carrier on Char Conversion and Its Implication for Chemical Looping Gasification
- 2022
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Ingår i: Energy & Fuels. - : American Chemical Society. - 0887-0624 .- 1520-5029. ; 36:17, s. 9768-9779
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Tidskriftsartikel (refereegranskat)abstract
- Chemical looping gasification (CLG) is an emerging process that aims to produce valuable chemical feedstocks. The key operational requirement of CLG is to limit the oxygen transfer from the air reactor (AR) to the fuel reactor (FR). This can be accomplished by partially oxidizing the oxygen carrier in the AR, which may lead to a higher reduction degree of the oxygen carrier under the fuel conversion. A highly reduced oxygen carrier may experience multiple issues, such as agglomeration and defluidization. Given such an interest, this study examined how the variation of the mass conversion degree of ilmenite may affect the conversion of pine forest residue char in a fluidized bed batch reactor. Ilmenite was pre-reduced using diluted CO and then underwent the char conversion at 850, 900, 950, and 975 °C. Our investigations showed that the activation energy of the char conversion was between 194 and 256 kJ/mol, depending upon the mass conversion degree of ilmenite. Furthermore, the hydrogen partial pressure in the particle bed increased as the oxygen carrier mass conversion degree decreased, which was accompanied by a lower reaction rate and a higher reduction potential. Such a hydrogen inhibition effect was confirmed in the experiments; therefore, the change in the mass conversion degree indirectly affected the char conversion. Langmuir-Hinshelwood mechanism models used to evaluate the char conversion were validated. On the basis of the physical observation and characterizations, the use of ilmenite in CLG with biomass char as fuel will likely not suffer from major agglomeration or fluidization issues.
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| 17. |
- Purnomo, Victor, 1992, et al.
(författare)
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Performance of iron sand as an oxygen carrier at high reduction degrees and its potential use for chemical looping gasification
- 2023
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 339
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Tidskriftsartikel (refereegranskat)abstract
- Iron sand as an industrial by-product has a reasonable iron content (35 wt% Fe) and low economical cost. The reactivity of iron sand as an oxygen carrier was examined in a bubbling fluidized bed reactor using both gaseous and solid fuels at 850–975 °C. Pre-reductions of iron sand were performed prior to fuel conversion to adapt the less-oxygen-requiring environment in chemical looping gasification (CLG). Based on the investigations using CO and CH4, iron sand has an oxygen transfer capacity of around 1 wt%, which is lower than that of ilmenite. The conversion of pine forest residue char to CO and H2 was higher when using iron sand compared to ilmenite. Depending on the mass conversion degree of iron sand, the activation energy of pine forest residue char conversion using iron sand was between 187 and 234 kJ/mol, which is slightly lower than that of ilmenite. Neither agglomeration nor defluidization of an iron sand bed occurred even at high reduction degrees. These suggests that iron sand can be utilized as an oxygen carrier in CLG. Furthermore, this study presents novel findings in the crystalline phase transformation of iron sand at various degrees of oxidation, altogether with relevant thermodynamic stable phases.
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| 18. |
- Saeed, Muhammad Nauman, 1995, et al.
(författare)
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Production of aviation fuel with negative emissions via chemical looping gasification of biogenic residues: Full chain process modelling and techno-economic analysis
- 2023
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Ingår i: Fuel Processing Technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 241
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Tidskriftsartikel (refereegranskat)abstract
- The second-generation bio aviation fuel production via Chemical Looping Gasification (CLG) of biomass combined with downstream Fischer-Tropsch (FT) synthesis is a possible way to decarbonize aviation sector. The CLG process has the advantage of producing undiluted syngas without the use of an air-separation unit (ASU) and improved syngas yield compared to the conventional gasification processes. This study is based on modelling the full chain process of biomass to liquid fuel (BtL) with LD-slag and Ilmenite as oxygen carriers using Aspen Plus software, validating the model results with experimental studies and carrying out a techno-economic analysis of the process. For the gasifier load of 80 MW based on LHV of fuel entering the gasifier, the optimal model predicts that the clean syngas has an energy content of 8.68 MJ/Nm3 with a cold-gas efficiency of 77.86%. The optimized model also estimates an aviation fuel production of around 340 bbl/day with 155 k-tonne of CO2 captured every year and conversion efficiency of biomass to FT-crude of 38.98%. The calculated Levelized Cost of Fuel (LCOF) is 35.19 $ per GJ of FT crude, with an annual plant profit (cash inflow) of 11.09 M$ and a payback period of 11.56 years for the initial investment.
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| 19. |
- Anjum, Misbah, et al.
(författare)
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A framework for optimal patch release time using G-DEMATEL and multi-attribute utility theory
- 2024
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Ingår i: International Journal of Industrial and Systems Engineering. - : Inderscience Publishers. - 1748-5037 .- 1748-5045. ; 46:4, s. 531-555
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Tidskriftsartikel (refereegranskat)abstract
- The primary focus of the present work is to determine the optimal vulnerability patch release time using multi-attribute utility theory (MAUT) by considering two objectives that are cost minimisation and reliability maximisation. The novelty of the study lies in multi-phased research methodology for identifying the attributes affecting the software patch release time through a combination of literature review and the grey-Delphi approach for guiding the optimisation process. The literature has directly considered the weights of the attributes without emphasising their interrelationships, which is overcome by the use of the DEMATEL methodology under the grey environment in the current study for the evaluation of weights of selected attributes. The implications of the study will help in achieving the sustainable development goals pertaining to innovation and infrastructure. A numerical example is used to demonstrate the relevance of the optimisation problem.
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| 20. |
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| 21. |
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| 22. |
- Das, A., et al.
(författare)
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Genomic predictors of response to PD-1 inhibition in children with germline DNA replication repair deficiency
- 2022
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 28:1, s. 125-135
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Tidskriftsartikel (refereegranskat)abstract
- Cancers arising from germline DNA mismatch repair deficiency or polymerase proofreading deficiency (MMRD and PPD) in children harbour the highest mutational and microsatellite insertion–deletion (MS-indel) burden in humans. MMRD and PPD cancers are commonly lethal due to the inherent resistance to chemo-irradiation. Although immune checkpoint inhibitors (ICIs) have failed to benefit children in previous studies, we hypothesized that hypermutation caused by MMRD and PPD will improve outcomes following ICI treatment in these patients. Using an international consortium registry study, we report on the ICI treatment of 45 progressive or recurrent tumors from 38 patients. Durable objective responses were observed in most patients, culminating in a 3 year survival of 41.4%. High mutation burden predicted response for ultra-hypermutant cancers (>100 mutations per Mb) enriched for combined MMRD + PPD, while MS-indels predicted response in MMRD tumors with lower mutation burden (10–100 mutations per Mb). Furthermore, both mechanisms were associated with increased immune infiltration even in ‘immunologically cold’ tumors such as gliomas, contributing to the favorable response. Pseudo-progression (flare) was common and was associated with immune activation in the tumor microenvironment and systemically. Furthermore, patients with flare who continued ICI treatment achieved durable responses. This study demonstrates improved survival for patients with tumors not previously known to respond to ICI treatment, including central nervous system and synchronous cancers, and identifies the dual roles of mutation burden and MS-indels in predicting sustained response to immunotherapy. © 2022, The Author(s).
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| 23. |
- Derakhshandeh, J., et al.
(författare)
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Fabrication of 100 nm gate length MOSFET's using a novel carbon nanotube-based nano-lithography
- 2005
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Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5107 .- 1873-4944. ; 124, s. 354-358
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Tidskriftsartikel (refereegranskat)abstract
- PECVD-grown carbon nanotubes on (100)silicon substrates have been studied and exploited for electron emission applications. After the growth of vertical CNT's [Y. Abdi, J. Koohsorkhi, J. Derakhshandeh, S. Mohajerzadeh, H. Hosseinzadegan, M.D. Robertson, C. Benet, EMRS Spring Meeting, Strasbourg, France, May 2005] the grown nanotubes are encapsulated by means of an insulating TiO(2) layer, leading to beam-shape emission of electrons from the cathode towards the opposite anode electrode. The electron emission occurs using an anode-cathode voltage of 100 V with ability of direct writing on a photo-resist-coated substrates. Straight lines with widths between 50 and 200 nm have been successfully drawn. This technique has been applied on P-type (100)silicon substrates for the formation of the gate of N-MOSFET devices. The successful realization of MOSFET devices indicates its usefulness for applications in nano-electronic devices. This device has inversion Cox exceeding 0.7 mu F/cm(2), drive current equal to 3 10 mu A/mu m.
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| 24. |
- Dickstein, D. L., et al.
(författare)
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Brain and blood biomarkers of tauopathy and neuronal injury in humans and rats with neurobehavioral syndromes following blast exposure
- 2021
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Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 26, s. 5940-5954
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Tidskriftsartikel (refereegranskat)abstract
- Traumatic brain injury (TBI) is a risk factor for the later development of neurodegenerative diseases that may have various underlying pathologies. Chronic traumatic encephalopathy (CTE) in particular is associated with repetitive mild TBI (mTBI) and is characterized pathologically by aggregation of hyperphosphorylated tau into neurofibrillary tangles (NFTs). CTE may be suspected when behavior, cognition, and/or memory deteriorate following repetitive mTBI. Exposure to blast overpressure from improvised explosive devices (IEDs) has been implicated as a potential antecedent for CTE amongst Iraq and Afghanistan Warfighters. In this study, we identified biomarker signatures in rats exposed to repetitive low-level blast that develop chronic anxiety-related traits and in human veterans exposed to IED blasts in theater with behavioral, cognitive, and/or memory complaints. Rats exposed to repetitive low-level blasts accumulated abnormal hyperphosphorylated tau in neuronal perikarya and perivascular astroglial processes. Using positron emission tomography (PET) and the [F-18]AV1451 (flortaucipir) tau ligand, we found that five of 10 veterans exhibited excessive retention of [F-18]AV1451 at the white/gray matter junction in frontal, parietal, and temporal brain regions, a typical localization of CTE tauopathy. We also observed elevated levels of neurofilament light (NfL) chain protein in the plasma of veterans displaying excess [F-18]AV1451 retention. These findings suggest an association linking blast injury, tauopathy, and neuronal injury. Further study is required to determine whether clinical, neuroimaging, and/or fluid biomarker signatures can improve the diagnosis of long-term neuropsychiatric sequelae of mTBI.
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| 25. |
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