733 research outputs found
An Investigation of Aural Space inside Mousa Broch by Observation and Analysis of Sound and Light
No full textThis project emphasises the unique character and construction of Mousa broch, questions the model of Mousa broch as a roofed home (an interpretation adopted by Historic Scotland in 2002) and considers the way in which sound and light informs our understanding of the spaces contained within its structure. Underpinning the approach to data collection was the architectural concept of aural space. The author attempts to convey an impression of aural space inside Mousa broch by the creation of an audio-visual record supported by acoustic analysis, archaeological discussion, and an architectural breakdown of the spaces within the broch structure. Audio recordings, sound samples, photographs and movies were made on Mousa island and inside Mousa broch during the period of the Summer solstice of 2009
Author Correction: the Influence of Nano Filter Elements on Pressure Drop and Pollutant Elimination Efficiency in Town Border Stations
No full textThe original version of this Article contained an error in the order of the author names, which was incorrectly given as Hamed Ebadiyan, Saeed Zeinali Heris, Seyed Borhan Mousavi, Shamin Hosseini Nami ; Mousa Mohammadpourfard. Consequently, in the Author Contributions section, “H.E. Investigation. S.Z.H. Supervision, Conceptualization, Methodology, Validation. S.B.M. Formal analysis, Writing original draft. S.H.N. Formal analysis, Writing original draft. M.M. Validation.” now reads: “S.Z.H. Supervision, Conceptualization, Methodology, Validation. H.E. Investigation. S.B.M. Formal analysis, Writing original draft. S.H.N. Formal analysis, Writing original draft. M.M. Validation.” The original Article has been corrected. © 2023, The Author(s)
SYNTHESIS OF C-GLYCOSYL AMINO ACIDS AS STABLE BUILDING BLOCKS FOR MODIFIED GLYCOPEPTIDE SYNTHESIS
No full textIn this thesis, we have studied and synthesized new class of C-glycosly amino acids whose structure features a
hetrocycle ring holding the carbohydrate and the amino acid fragments. Pyridine and tetrazole rings were used as
hetrocycle linkers in this project. This class of C-glycosyl amino acids is of interest as new chealtors and as building
building blocks for cotranslational glycopeptides synthesis. In the first part, C-Glycosylmethyl pyridylalanines were
synthesized via thermally induced Hantzsch-type cyclocondensation using an aldehyde-ketoester-enamino ester system.
To one of these reagents was attached a C-glycosyl residue, while to another was bound an amino acid fragment. In a
one-pot optimized methodology, the dihydropyridine was not isolated while its purification was carried out by removal
of unreacted material and side products using polymer-supported scavengers. Then the dihydropyridine (mixture of
diastereoisomers) was oxidized by a polymer-bound oxidant to give the target pyridine bearing the two bioactive
residues. In this way, a range of eight compounds (58-68% yield) was prepared in which the elements of diversity were
(i) the gluco and galacto configurations of the pyranose ring, (ii) the α- and β-configurations at the anomeric center, and
(iii) the positions of the carbohydrate and amino acid sectors in the pyridine ring. The orthogonal functional group
protection in these amino acids allowed their easy incorporation into oligopeptides via sequential amino and carboxylic
group coupling.
In the second part, tetrazole moiety was constructed via Huisgen 1,3-dipolar cycloaddition between nitriles and organic
azides. Two sets of compounds have been prepared, one being constituted of C-galactosyl and C-ribosyl O-tetrazolyl
serines, while the other contains S-tetrazolyl cysteine derivatives. In both cases, the synthetic scheme involved a twostep
route: the first one being the thermal cycloaddition of a sugar azide with p-toluensulfonyl cyanide (TsCN) to give a
1-substituted 5-sulfonyl tetrazole and the second the replacement of the tosyl group with a serine or cysteine residue.
For the high efficiency and operational simplicity, the azide-TsCN cycloaddition appears to be a true click process.
Finally, one of the amino acids prepared was incorporated into a tripeptid
Ligniinipohjaisen biohiilen käyttö metallurgisissa sovelluksissa
No full textAbstractPyrometallurgical processes in the iron and steel industry are energy intensive. Therefore, sustainability in terms of CO2 emissions is highly dependent on the choice of fuel. Large quantities of carbon are used in pyrometallurgical processes, for example in slag foaming, iron oxide reduction or as an alloying element. Currently, the majority of the used carbon originates from fossil sources.The most important properties that are generally required from carbonaceous materials in pyrometallurgical applications are mechanical strength, sufficient apparent density and suitable reactivity. The properties of industrially produced metallurgical coke works as a great reference for evaluation of these properties, since metallurgical coke is used in multiple pyrometallurgical applications in different forms: coke dust is used as a foaming agent and carburiser in the electric arc furnace (EAF) process, and coke lumps are used as a reducing agent and structural bed material in the blast furnace (BF) process and as a reducing agent in submerged arc furnace (SAF) process.This thesis focuses on the utilisation of hydrolysis lignin as a raw material for the production of biocarbon that could be utilised as a carbonaceous material in pyrometallurgical applications to substitute fossil-based carbon. Based on the results of this thesis, it was discovered that the structure of lignin-based biocarbon can be modified using the chosen treatment methods, briquetting and high pyrolysis temperature. With these treatment methods, the important properties (mechanical strength, apparent density and reactivity) were improved and modified, with the compressive strength property of biocarbon even surpassing that of metallurgical coke.Original papersOriginal papers are not included in the electronic version of the dissertation.Koskela, A., Suopajärvi, H., Mattila, O., Uusitalo, J., & Fabritius, T. (2019). Lignin from bioethanol production as a part of a raw material blend of a metallurgical coke. Energies, 12(8), 1533. https://doi.org/10.3390/en12081533Self-archived versionKoskela, A., Heikkilä, A., Bergna, D., Salminen, J., & Fabritius, T. (2021). Effects of briquetting and high pyrolysis temperature on hydrolysis lignin char properties and reactivity in CO-CO2-N2 conditions. Minerals, 11(2), 187. https://doi.org/10.3390/min11020187Self-archived versionKoskela, A., Suopajärvi, H., & Fabritius, T. (2022). Interaction between coal and lignin briquettes in co-carbonization. Fuel, 324, 124823. https://doi.org/10.1016/j.fuel.2022.124823Self-archived versionKoskela, A., Suopajärvi, H., Uusitalo, J., & Fabritius, T. (2023). Evolution of biocarbon strength and structure during gasification in CO2 containing gas atmosphere. Fuel Communications, 14, 100082. https://doi.org/10.1016/j.jfueco.2022.100082Self-archived versionTiivistelmäTerästeollisuuden pyrometallurgiset prosessit ovat energiaintensiivisiä. Sen vuoksi terästeollisuuden ekologisuus CO2 päästöjen osalta on erittäin riippuvainen polttoainevalinnasta. Suuria määriä hiiltä käytetään pyrometallurgisissa prosesseissa, esimerkiksi kuonan kuohutuksessa, raudan oksidien pelkistyksessä tai seosaineena. Nykyään suurin osa käytetystä hiilestä on lähtöisin fossiilisista lähteistä.Pyrometallurgisissa prosesseissa käytettäviltä hiilimateriaaleilta vaadittuja tärkeimpiä ominaisuuksia ovat mekaaninen lujuus, riittävä näennäistiheys ja sopiva reaktiivisuus. Teollisesti valmistetun metallurgisen koksin ominaisuudet sopivat hyvin näiden ominaisuuksien vertailukohdaksi, sillä koksia käytetään useissa eri sovelluksissa eri muodoissa: koksipölyä käytetään kuonan kuohutusaineena ja hiilen tuojana valokaariuuniprosessissa, palakoksia pelkistimenä ja rakenteellisena petimateriaalina masuunissa sekä pelkistimenä uppokaariuunissa.Tämä työ keskittyy hydrolyysiligniinin hyötykäyttöön raaka-aineena biohiilen ja biokoksin valmistuksessa, joita voidaan käyttää hiilen tuojana pyrometallurgisissa sovelluksissa korvaamaan fossiilista lähteistä tuotettua hiiltä. Tämän työn tulosten perusteella hydrolyysiligniini-pohjaisen biohiilen rakennetta pystyttiin muokkaamaan valituilla käsittelymenetelmillä, briketoinnilla ja korkealla pyrolyysilämpötilalla. Näillä menetelmillä biohiilen tärkeitä ominaisuuksia (mekaaninen lujuus, näennäistiheys ja reaktiivisuus) saatiin parannettua siten, että biohiilen puristuslujuus oli jopa suurempi kuin metallurgisella koksilla.OsajulkaisutOsajulkaisut eivät sisälly väitöskirjan elektroniseen versioon.Koskela, A., Suopajärvi, H., Mattila, O., Uusitalo, J., & Fabritius, T. (2019). Lignin from bioethanol production as a part of a raw material blend of a metallurgical coke. Energies, 12(8), 1533. https://doi.org/10.3390/en12081533Rinnakkaistallennettu versioKoskela, A., Heikkilä, A., Bergna, D., Salminen, J., & Fabritius, T. (2021). Effects of briquetting and high pyrolysis temperature on hydrolysis lignin char properties and reactivity in CO-CO2-N2 conditions. Minerals, 11(2), 187. https://doi.org/10.3390/min11020187Rinnakkaistallennettu versioKoskela, A., Suopajärvi, H., & Fabritius, T. (2022). Interaction between coal and lignin briquettes in co-carbonization. Fuel, 324, 124823. https://doi.org/10.1016/j.fuel.2022.124823Rinnakkaistallennettu versioKoskela, A., Suopajärvi, H., Uusitalo, J., & Fabritius, T. (2023). Evolution of biocarbon strength and structure during gasification in CO2 containing gas atmosphere. Fuel Communications, 14, 100082. https://doi.org/10.1016/j.jfueco.2022.100082Rinnakkaistallennettu versioAcademic dissertation to be presented with the assent of the Doctoral Programme Committee of Technology and Natural Sciences of the University of Oulu for public defence in the OP auditorium (L10), Linnanmaa, on 12 May 2023, at 12 noonAbstract
Pyrometallurgical processes in the iron and steel industry are energy intensive. Therefore, sustainability in terms of CO2 emissions is highly dependent on the choice of fuel. Large quantities of carbon are used in pyrometallurgical processes, for example in slag foaming, iron oxide reduction or as an alloying element. Currently, the majority of the used carbon originates from fossil sources.
The most important properties that are generally required from carbonaceous materials in pyrometallurgical applications are mechanical strength, sufficient apparent density and suitable reactivity. The properties of industrially produced metallurgical coke works as a great reference for evaluation of these properties, since metallurgical coke is used in multiple pyrometallurgical applications in different forms: coke dust is used as a foaming agent and carburiser in the electric arc furnace (EAF) process, and coke lumps are used as a reducing agent and structural bed material in the blast furnace (BF) process and as a reducing agent in submerged arc furnace (SAF) process.
This thesis focuses on the utilisation of hydrolysis lignin as a raw material for the production of biocarbon that could be utilised as a carbonaceous material in pyrometallurgical applications to substitute fossil-based carbon. Based on the results of this thesis, it was discovered that the structure of lignin-based biocarbon can be modified using the chosen treatment methods, briquetting and high pyrolysis temperature. With these treatment methods, the important properties (mechanical strength, apparent density and reactivity) were improved and modified, with the compressive strength property of biocarbon even surpassing that of metallurgical coke.Tiivistelmä
Terästeollisuuden pyrometallurgiset prosessit ovat energiaintensiivisiä. Sen vuoksi terästeollisuuden ekologisuus CO2 päästöjen osalta on erittäin riippuvainen polttoainevalinnasta. Suuria määriä hiiltä käytetään pyrometallurgisissa prosesseissa, esimerkiksi kuonan kuohutuksessa, raudan oksidien pelkistyksessä tai seosaineena. Nykyään suurin osa käytetystä hiilestä on lähtöisin fossiilisista lähteistä.
Pyrometallurgisissa prosesseissa käytettäviltä hiilimateriaaleilta vaadittuja tärkeimpiä ominaisuuksia ovat mekaaninen lujuus, riittävä näennäistiheys ja sopiva reaktiivisuus. Teollisesti valmistetun metallurgisen koksin ominaisuudet sopivat hyvin näiden ominaisuuksien vertailukohdaksi, sillä koksia käytetään useissa eri sovelluksissa eri muodoissa: koksipölyä käytetään kuonan kuohutusaineena ja hiilen tuojana valokaariuuniprosessissa, palakoksia pelkistimenä ja rakenteellisena petimateriaalina masuunissa sekä pelkistimenä uppokaariuunissa.
Tämä työ keskittyy hydrolyysiligniinin hyötykäyttöön raaka-aineena biohiilen ja biokoksin valmistuksessa, joita voidaan käyttää hiilen tuojana pyrometallurgisissa sovelluksissa korvaamaan fossiilista lähteistä tuotettua hiiltä. Tämän työn tulosten perusteella hydrolyysiligniini-pohjaisen biohiilen rakennetta pystyttiin muokkaamaan valituilla käsittelymenetelmillä, briketoinnilla ja korkealla pyrolyysilämpötilalla. Näillä menetelmillä biohiilen tärkeitä ominaisuuksia (mekaaninen lujuus, näennäistiheys ja reaktiivisuus) saatiin parannettua siten, että biohiilen puristuslujuus oli jopa suurempi kuin metallurgisella koksilla
Lyapunov-Based Model Predictive Control for Stable Operation of a 9-Level Crossover Switches Cell Inverter in Grid Connection Mode
No full textThis study proposes the application of a Lyapunov-based Model Predictive Control (L-MPC) approach to a 9-level Crossover Switches Cell (CSC9) converter operating in grid connection mode. The proposed method utilizes the structure of the classical finite-control-set MPC (FCS-MPC) technique while integrating a cost function that requires no tuning. By deriving the cost function based on Lyapunov theory, the system stability is ensured. Notably, the suggested approach offers several advantages over traditional MPC controllers. Firstly, it eliminates the need for gain tuning, thereby simplifying the implementation process. Secondly, the proposed controller prioritizes stability as a key design aspect. The presented simulation results prove that the proposed controller effectively regulates the voltage of the DC capacitor around its desired value and feed a smooth sinusoidal current to the grid with low total harmonic distortion (THD) while operating at a unity power factor.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.DC systems, Energy conversion & Storag
Reduction of iron ore burden materials mixed with nut coke under simulated blast furnace conditions
No full textModern blast furnace ironmaking technology: potentials to meet the demand of high hot metal production and lower energy consumption
No full textIron and steel making is one of the most intense energy consuming in the industrial sectors. The intensive utilization of fossil carbon in the ironmaking blast furnace (BF) is related directly to CO2 emission and global warming. Lowering the energy consumption and CO2 emission from BF comes on the top priorities from both economic and environmental aspects. The BF has undergone tremendous modifications and development to increase production and improve the overall efficiency. Both technological development and scientific research drive one another to reach optimum operation conditions, which are very close to the ideal conditions; however, further development is still required to meet the stringent environmental regulations. The present article provides a comprehensive review of recent research and development which were carried out in modern blast furnace to increase the productivity meanwhile reduce the energy consumption and CO2 emission to meet the demand of steel market and the environmental protection. The recent technological and metallurgical improvements in the BF are intensively discussed including: (i) modifications of BF design, top charging and measuring system, (ii) upgrading of conventional top charging burden and alternative agglomerates, (iii) developing of tuyeres injection system and injected materials, and (iv) potentials of waste heat recovery and usage. These topics are reviewed and discussed in some details to elucidate the potential of recent progress in BF technology in saving the energy consumption and lowering CO2 emission. In this paper, the major research and development which have been carried out in ironmaking BF technology are reviewed with an overview of the future prospects
Reduction of iron ore burden materials mixed with nut coke under simulated blast furnace conditions
No full textA benchmark study of the multiscale and homogenization methods for fully implicit multiphase flow simulations
No full textAccurate simulation of multiphase flow in subsurface formations is challenging, as the formations span large length scales (km) with high-resolution heterogeneous properties. To deal with this challenge, different multiscale methods have been developed. Such methods construct coarse-scale systems, based on a given high-resolution fine-scale system. Furthermore, they are amenable to parallel computing and allow for a-posteriori error control. The multiscale methods differ from each other in the way the transition between the different scales is made. Multiscale (finite element and finite volume) methods compute local basis functions to map the solutions (e.g. pressure) between coarse and fine scales. Instead, homogenization methods solve local periodic problems to determine effective models and parameters (e.g. permeability) at a coarser scale. It is yet unknown how these two methods compare with each other, especially when applied to complex geological formations, with no clear scale separation in the property fields. This paper develops the first comparison benchmark study of these two methods and extends their applicability to fully implicit simulations using the algebraic dynamic multilevel (ADM) method. At each time step, on the given fine-scale mesh and based on an error analysis, the fully implicit system is solved on a dynamic multilevel grid. The entries of this system are obtained by using multiscale local basis functions (ADM-MS), and, respectively, by homogenization over local domains (ADM-HO). Both sets of local basis functions (ADM-MS) and local effective parameters (ADM-HO) are computed at the beginning of the simulation, with no further updates during the multiphase flow simulation. The two methods are extended and implemented in the same open-source DARSim2 simulator (https://gitlab.com/darsim2simulator), to provide fair quality comparisons. The results reveal insightful understanding of the two approaches, and qualitatively benchmark their performance. It is re-emphasized that the test cases considered here include permeability fields with no clear scale separation. The development of this paper sheds new lights on advanced multiscale methods for simulation of coupled processes in porous media.Reservoir EngineeringNumerical Analysi
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