| 51. |
- Abdolahi-Mansoorkhani, Hamed, et al.
(author)
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CO 2 capture by modified hollow fiber membrane contactor: Numerical study on membrane structure and membrane wettability
- 2020
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In: Fuel Processing Technology. - : Elsevier BV. - 0378-3820. ; 209
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Journal article (peer-reviewed)abstract
- This work aims at capturing CO2 from natural gas using a verified finite element mathematical model by improving the membrane wettability, membrane structure, the type of absorbents used in the system, and the physical parameters like membrane porosity and the number of fibers used in hollow fiber membrane contactor (HFMC). The model is developed to simulate the CO2 removal using membranes by considering mass transfer equations in the presence of chemical reactions. Simulations were performed using a membrane system including 10 fibers with 175 mm length, 830 μm outer fiber radius and 450 μm inner fiber radius. The effect of adding montmorillonite nanoparticles (MMT) in weight percentages of 1%, 3%, and 5% to the PVDF membrane was perused to demonstrate the influence of membrane structure modification on system performance. The results show that the modification of membrane structure with montmorillonite nanoparticles could increase the efficiency of the system in the removal of CO2 particles by 8%. Four absorbents including MEA (monoethanol amine), PZ (piperazine), TEA (triethanolamine), and EDA (ethylenediamine) are used to identify the most effective absorbent where PZ absorbent shows the highest and EDA absorbent has the lowest carbon capture efficiency. Wettability is found to have a considerably negative impact on membrane carbon capture capacity. For instance, the modeling results show that even a 10% wetting of the membrane reduces the efficiency of the CO2 removal process by more than 47%. In addition, the results illustrate that the increase in membrane tortuosity and gas velocity have negative impacts on the separation process, while increase in the absorbent concentration, packing density and porosity enhance the separation of CO2.
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| 52. |
- Abdollahi, Mehdi, 1985, et al.
(author)
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A novel cold biorefinery approach for isolation of high quality fish oil in parallel with gel-forming proteins
- 2020
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In: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 332
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Journal article (peer-reviewed)abstract
- The pH-shift process for isolation of gel-forming proteins from fish processing by-products was extended to allow parallel isolation of fish oil. Subjecting the floating emulsion layer formed during pH-shift processing of salmon by-products to pH-adjustment or freeze/thawing efficiently released the emulsified oil at 4 °C. However, for herring by-products higher temperature (10 °C) and a combination of the emulsion-breaking techniques was required for efficient oil release. Oil recovery yield using the adjusted pH-shift process was lower than with classic heat-induced oil isolation (90 °C/20 min), but pH-shift-produced oils had higher amounts of n-3 polyunsaturated fatty acids (n-3 PUFA). Also, alkaline pH-shift processing produced oils with remarkably less oxidation products and free fatty acids compared with acid pH-shift process or heat-induced isolation. Extending the pH-shift process with emulsion breaking techniques can thus be a promising biorefinery approach for parallel cold production of high-quality fish oil and gel-forming proteins from fish by-products.
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| 53. |
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| 54. |
- Abdollahi, Mehdi, 1985, et al.
(author)
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Impact of processing technology on macro- and micronutrient profile of protein-enriched products from fish backbones
- 2021
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In: Foods. - : MDPI AG. - 2304-8158. ; 10:5
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Journal article (peer-reviewed)abstract
- Impacts of processing technology (mechanical separation and pH-shift processing) on protein recovery from salmon, herring and cod backbones and the content of macro- and micronutrients in the recovered protein enriched products were investigated. Mechanical separation led to higher protein recovery compared with the pH-shift process and using both techniques, recovery ranked the species as herring > salmon > cod. However, the pH-shift process up-concentrated protein from herring and salmon backbones more efficiently than mechanical separation by removing more fat and ash. This consequently reduced n-3 PUFA and vitamin D content in their protein isolates compared with the backbones and mechanically separated meat (MSM). Cod protein isolate, however, contained higher levels of these nutrients compared with MSM. Mechanical separation concentrated vitamins E and C in salmon MSM but not for cod and herring. Opposite, pH-shift processing reduced levels of these two vitamins for cod and herring backbones, while vitamins D and C were reduced for salmon. For minerals, selenium, calcium, magnesium, and potassium were lower in protein isolates than MSM, while copper, zinc, iron and manganese were similar or higher. Overall, there is a major potential for upcycling of fish backbones to food ingredients, but processing technology should be carefully balanced against the desired nutrient profile and final application area.
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| 55. |
- Abdollahi, Mehdi, 1985, et al.
(author)
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Minimizing lipid oxidation during pH-shift processing of fish by-products by cross-processing with lingonberry press cake, shrimp shells or brown seaweed
- 2020
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In: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 327
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Journal article (peer-reviewed)abstract
- The potential of cross-processing herring or salmon by-products with brown seaweed, shrimp peeling by-products and lingonberry press cake (called “helpers”) to minimize lipid oxidation during acid/alkaline pH-shift protein isolation was evaluated. Lingonberry press cake remarkably reduced levels of lipid hydroperoxides, malondialdehyde (MDA) and 4-hydroxy-trans2-hexenal (HHE) in both herring and salmon protein isolates (PI) while seaweed and shrimp by-product mitigated generation of MDA and HHE in herring PI. The salmon PI, however, by itself had very low oxidation levels. Cross-processing reduced protein yield compared with the classical pH-shift process by diminishing protein solubility, but still, the alkaline process version was promising. The color of the PIs varied greatly between different process combinations, reflecting partitioning of natural pigments into isolates. Altogether, cross-processing seems a promising tool for inhibition of lipid oxidation during pH-shift processing of sensitive fish by-products, with the alkaline version and lingonberry press cake being closest at hand for further studies.
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| 56. |
- Abdolshahi, Anna, et al.
(author)
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Edible Film Based on Lallemantia peltata L. Seed Gum: Development and Characterization
- 2022
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In: Journal of Chemical Health Risks. - 2251-6719 .- 2251-6727. ; 12:1, s. 47-61
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Journal article (peer-reviewed)abstract
- A novel edible film was developed using Lallemantia peltata (L.) seed gum (LSG), and its water sensitivity, physico-mechanical, barriers, microstructural and thermal properties as a function of glycerol concentration (20, 30, 40, 50 and 60% w/w) were studied. Different models were also used to investigate the water sorption of the LSG films. Unplasticized LSG films were brittle and difficult to handle which were effectively modified by glycerol addition. Water sensitivity, oxygen permeability, and elongation of LSG films were increased with increasing glycerol concentration. Also, increasing of glycerol concentration resulted in reduction of tensile strength, glass transition temperature (Tg) and melting temperature (Tm) of the films. Electron scanning micrographs revealed a smooth surfaceand compact cross-section microstructure in LSG films.The films showed sigmoid shape type II water sorption isotherms, representing typical features of most of biopolymers. Accordingly, the results suggest that LSG films containing desired glycerol concentration could potentially be used as edible films in food packaging.
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| 57. |
- Abdul-Jabbar, Thealfaqar A., et al.
(author)
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Efficient Battery Cell Balancing Methods for Low-Voltage Applications: A Review
- 2022
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In: 2022 IEEE International Conference in Power Engineering Application, ICPEA 2022 - Proceedings.
-
Conference paper (peer-reviewed)abstract
- Battery balancing technologies are a crucial mech anism for the safe operation of electrochemical energy storage systems, such as lithium-ion batteries. Moreover, balancing be tween battery cells is essential for battery systems' life. Without any balancing circuitry, individual cell voltages can reach their maximum/minimum battery voltage limit faster than others, posing safety hazards. Furthermore, battery capacity reduction can occur when overcharging/over-discharging individual cells. So far, many balancing methodologies have been proposed and discussed in available literature. This paper presents a review of different state-of-The-Art cell balancing methods suitable for low voltage applications. The required control complexity, switch stress, balancing speed, cost and circuit size are considered as key aspects. Typically, cell bypass techniques, such as passive balancing, have the lowest cost and require no complex control strategies. In contrast, cell-To-cell balancing techniques can significantly increase the energy efficiency compared to cell bypass balancers, but these come with higher system costs and control complexity.
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| 58. |
- Abdurrokhman, Iqbaal, 1991
(author)
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Binary mixtures and cationic modification of protic ionic liquids. Local structure and transport properties
- 2021
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Doctoral thesis (other academic/artistic)abstract
- Protic ionic liquids are a subclass of ionic liquids, which in many cases are obtained by mixing an equimolar amount of Brønsted acid and base. Protic ionic liquids possess an exchangeable proton that gives them distinct features, e.g. the potential to conduct protons and the ability to form extended hydrogen bonds, which is different from the case of their aprotic counterparts. The protic ionic liquids considered in this thesis are limited to those based on the imidazolium and triazolium cation, which (compared to aprotic ionic liquids) are less developed and have been investigated to a lesser extent. The work included in this thesis has been devoted to investigate strategies that could possibly promote a fast proton motion. These strategies have primarily consisted in mixing a protic ionic liquid with a molecular solvent or another parented ionic liquid and in modifying the cationic structure by either attaching alkyl chains of different length to the imidazolium cation or synthesizing new protic ionic liquids derived from another heterocyclic ring such as triazole. In both cases, a detailed characterization by means of vibrational spectroscopy could provide valuable information about intermolecular interactions. An important finding from the studies conducted in this thesis is that altering the cation's structure or adding a co-solvent leads to a significant change in chemical and transport properties. This thesis also includes an extensive work devoted to develop a new solvent-free method to synthesize dry and pure protic ionic liquids, in the laboratory scale. An analytical approach to accurately quantify their purity using nuclear magnetic spectroscopy has also been developed. In addition, the ionic conductivity of the investigated protic ionic liquid systems has been evaluated by use of impedance spectroscopy, from room temperature up to 140 °C. The results included in my work indicate that the two investigated strategies can potentially be used, each with its limitations, to develop thermochemically stable proton conducting materials based on protic ionic liquids.
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| 59. |
- Abdurrokhman, Iqbaal, 1991, et al.
(author)
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Binary Mixtures of Imidazolium-Based Protic Ionic Liquids. Extended Temperature Range of the Liquid State Keeping High Ionic Conductivities
- 2022
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In: Frontiers in Chemistry. - : Frontiers Media SA. - 2296-2646. ; 10
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Journal article (peer-reviewed)abstract
- Binary mixtures based on the two protic ionic liquids 1-ethylimidazolium triflate ([C2HIm][TfO]) and 1-ethylimidazolium bis(trifluoromethanesulfonyl)imide ([C2HIm][TFSI]) have been investigated, with focus on phase behavior, ionic conductivity, and intermolecular interactions as a function of composition (χTFSI indicating the mole fraction of the added compound). It is found that on addition of [C2HIm][TFSI] to [C2HIm][TfO], the melting temperature is first decreased (0 (Formula presented.) 0.3) and then suppressed (0.3 (Formula presented.) 0.8) resulting in mixtures with no phase transitions. These mixtures display a wide temperature range of the liquid state and should be interesting for use in devices operating at extreme temperatures. The ionic conductivity does not vary significantly across the composition range analyzed, as evidenced in the comparative Arrhenius plot. The activation energy, Ea, estimated by fitting with the Arrhenius relation in a limited temperature range (between 60 and 140 °C) varies marginally and keeps values between 0.17 and 0.21 eV. These marginal differences can be rationalized by the initially very similar values of the two neat protic ionic liquids. Vibrational spectroscopy, including both Raman and infrared spectroscopies, reveals weakening of the cation–anion interactions for increasing content of [C2HIm][TFSI], which is reflected by the blue shift of the average N-H stretching mode and the red shift of the S-O stretching mode in the TfO anion. These trends correlate with the higher disorder in the mixtures observed by DSC and are evidenced by the decrease and suppression of the melting temperature as the amount of [C2HIm][TFSI] is increased.
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| 60. |
- Abdurrokhman, Iqbaal, 1991
(author)
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Proton conducting ionic liquids-Binary mixtures and structural modifications
- 2020
-
Licentiate thesis (other academic/artistic)abstract
- Proton conduction is a phenomenon of fundamental importance for biological and chemical systems, such as in photosynthesis and aerobic respiration. Proton conduction is also key in the proton exchange membrane fuel cell, a clean electrochemical device that converts chemical into electrical energy. The archetypical proton exchange membrane is currently a perfluorinated polymer with pending acidic groups. The fuel cell technology is presently at renewed focus in the commercial sector, and consequently also in the scope of research and development programs. In order to enable the development of more sustainable proton exchange membrane fuel cells, new requirements have been set that for instance target operation at higher temperatures and anhydrous conditions. In this context, protic ionic liquids have been highlighted as interesting next-generation electrolytes with the potential to assist proton conduction. Protic ionic liquids are a subset of ionic liquids, also known as low temperature molten salts, entirely composed of ions and displaying very low vapor pressures. Moreover, a protic ionic liquid has an exchangeable proton and is able to establish extended networks of hydrogen bonds. Understanding the dynamics of this local structures is fundamental to design new protic ionic liquids able to sustain a fast proton motion decoupled from the diffusion of the ionic species. To achieve such a dynamical behavior we have investigated two different approaches, that is i) mixing a protic ionic liquid candidate with a co-solvent (here ethylene glycol) able to participate in the hydrogen bonds and ii) modifying the molecular structure of the cation (here by alkyl chains of length (n) varying from ethyl (n=2) to dodecyl (n=12)) in a series of imidazolium based protic ionic liquids. The local intermolecular inter- actions, the nano-structuration as well as ionic and protonic dynamics have been investigated by suitable techniques that include vibrational spectroscopy, NMR spectroscopy, diffusion NMR, impedance spectroscopy and X-ray scattering.
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