Sustainable CO2 adsorbents prepared by coating chitosan onto mesoporous silicas for large-scale carbon capture technology

In this article, we report a new sustainable synthesis procedure for manufacturing chitosan/silica CO2 adsorbents. Chitosan is a naturally abundant material and contains amine functionality, which is essential for selective CO2 adsorptions. It is, therefore, ideally suited for manufacturing CO2 adsorbents on a large scale. By coating chitosan onto high-surface-area mesoporous silica supports, including commercial fumed silica (an economical and accessible reagent) and synthetic SBA-15 and MCF silicas, we have prepared a new family of CO2 adsorbents, which have been fully characterised with nitrogen adsorption isotherms, thermogravimetric analysis/differential scanning calorimetry, TEM, FTIR spectroscopy and Raman spectroscopy. These adsorbents have achieved a significant CO2 adsorption capacity of up to 0.98 mmol g−1 at ambient conditions (P=1 atm and T=25 °C). The materials can also be fully regenerated/recycled on demand at temperatures as low as 75 °C with a >85 % retention of the adsorption capacity after 4 cycles, which makes them promising candidates for advanced CO2 capture, storage and utilisation technology

South Pacific Security and the Emerging Doctrine of \u27Co-operative Intervention\u27: the Pacific way or Howard\u27s way

The end of the Cold war catalysed considerable recalibration in the world\u27s security architecture. In Australia, whilst this entailed a closer embrace of Asia, the South Pacific did not initially engage Australian security interests. However, post 11 September 2001 and post the terrorist attacks in Bali of October 2002, much has changed. The notion of \u27comprehensive security\u27—in which Pacific security is seen as a function of a wide variety of social, political and strategic phenomena—has assumed such prominence it has ushered in an expanded justification for one state to intervene in the affairs of another. Although, as in the case of the Regional Assistance Mission to the Solomon Islands, such intervention has required invitation and multinational coalitions under the rubric \u27cooperative intervention\u27, the extent and nature of Australian-led initiatives in the South Pacific has raised concerns. Key amongst these concerns is the extent to which policies such as tied-aid and \u27extended cooperation\u27 might erode South Pacific sovereignty and the consensus politics of the Pacific Way. This article considers these issues against the backdrop of very significant changes to the region\u27s key political body, the Pacific Forum. It suggests that although Australia is commendably active in strengthening the Pacific\u27s security net, greater sensitivity to Pacific concerns might better effect her longer-term security objectives

Nonlinear response theory for Markov processes: Simple models for glassy relaxation

The theory of nonlinear response for Markov processes obeying a master equation is formulated in terms of time-dependent perturbation theory for the Green's functions and general expressions for the response functions up to third order in the external field are given. The nonlinear response is calculated for a model of dipole reorientations in an asymmetric double well potential, a standard model in the field of dielectric spectroscopy. The static nonlinear response is finite with the exception of a certain temperature $T_0$ determined by the value of the asymmetry. In a narrow temperature range around $T_0$, the modulus of the frequency-dependent cubic response shows a peak at a frequency on the order of the relaxation rate and it vanishes for both, low frequencies and high frequencies. At temperatures at which the static response is finite (lower and higher than $T_0$), the modulus is found to decay monotonously from the static limit to zero at high frequencies. In addition, results of calculations for a trap model with a Gaussian density of states are presented. In this case, the cubic response depends on the specific dynamical variable considered and also on the way the external field is coupled to the kinetics of the model. In particular, a set of different dynamical variables is considered that gives rise to identical shapes of the linear susceptibility and only to different temperature dependencies of the relaxation times. It is found that the frequency dependence of the nonlinear response functions, however, strongly depends on the particular choice of the variables. The results are discussed in the context of recent theoretical and experimental findings regarding the nonlinear response of supercooled liquids and glasses.Comment: 23 pages, 10 figure

Thermally regenerable carbon dioxide absorbent system Final report, 1 May 1964 - 31 Jan. 1966

Carbon dioxide absorption by solid state ion exchange resin

The effect of central counterparties on counterparty risk, liquidity and systemic risk of Over-the-Counter markets

The introduction of central clearing on formerly bilaterally cleared derivatives markets has been one of the biggest changes in the landscape of financial markets during the last decade. The studies in this thesis examine this landmark in financial markets regulation by analyzing its effect on three relevant areas of financial market stability: counterparty risk, market liquidity and systemic risk. The studies in this dissertation examine the effect of central clearing on these three areas empirically on the market for Credit Default Swaps (CDS) by using data from the Depository Trust & Clearing Corporation (DTCC). The results show that the option to clear trades with an arguably very creditworthy Central Clearing Counterparty (CCP) leads to varying effects depending on the risk profile of the CDS contracts. In chapter 2, we show that the introduction of central clearing decreases the netting efficiency of CDS contracts and leads to a higher fragmentation of CDS positions. This negative effect is concentrated in CDS contracts that were relatively efficiently netted in bilateral markets. The netting efficiency of ex-ante less efficiently netted CDS contracts, however, is not decreased by the introduction of central clearing. In chapter 3, I use a regression discontinuity design to show that central clearing affects market liquidity of CDS contracts positively. This effect, however, is concentrated in CDS contracts with high fundamental risk and high liquidity risk. Furthermore, I show that the positive liquidity effect can be explained by a lower sensitivity of market liquidity to counterparty risk and lower regulatory costs. In chapter 4, we use different time series techniques in order to show that the default dependencies among the dominant CDS market participants decrease with the introduction of central clearing. All in all, the results show the potentially stabilizing effect of CCPs on the financial market architecture of derivatives markets. However, this effect depends on the contracts that are made eligible for central clearing by CCPs. High-risk contracts exhibit by far the highest benefits from the central clearing option. For CCPs, however, low-risk contracts of high liquidity and high trading volumes may be most attractive to make eligible for central clearing as they maximize revenues and minimize risk management costs. This shows the conflict between regulators and regulated entities and the necessity of bespoke financial markets regulation.Die Einführung des zentralen Clearings auf früher bilateral geclearten Derivatemärkten war eine der größten Veränderungen der Finanzmarktarchitektur in der letzten Dekade. Die Kapitel dieser Dissertation untersuchen den Effekt dieses Meilensteins der Finanzmarktregulierung auf drei relevante Teilbereiche von Finanzmarktstabilität: Kontrahentenrisiko, Marktliquidität und systemisches Risiko. Die vorliegende Dissertation untersucht die Einführung des zentralen Clearings empirisch auf dem Markt für Credit Default Swaps unter Verwendung von Daten der Depository Trust & Clearing Corporation (DTCC). Die Ergebnisse zeigen, dass die Option der Handelsabwicklung mit einer sehr solventen Central Clearing Counterparty (CCP) zu unterschiedlichen Effekten je nach Risikoprofil der CDS-Kontrakte führt. In Kapitel 2 zeigen wir, dass die Nettingeffizienz von CDS-Kontrakten durch Einführung des zentralen Clearings abnimmt und somit zu einer höheren Fragmentierung der Handelspositionen auf dem CDS-Markt führt. Dieser negative Effekt konzentriert sich jedoch in CDS-Kontrakten, die auf dem bilateralen Markt relativ effizient saldiert wurden, während die Nettingeffizienz von ex-ante weniger effizient saldierten Kontrakte keine Reduktion der Nettingeffizienz erfährt. In Kapitel 3 zeige ich mithilfe einer Regressionsdiskontinuitätsanalyse, dass das zentrale Clearing die Marktliquidität von Kontrakten insgesamt positiv beeinflusst. Dieser Effekt konzentriert sich jedoch in Kontrakten, die vor Einführung einer CCP eine geringe Liquidität und ein hohes Fundamentalrisiko aufwiesen. Zudem zeige ich, dass der positive Liquiditätseffekt durch eine geringere Rolle des Kontrahentenrisikos und geringere regulatorische Kosten erklärt werden kann. Im vierten Kapitel der Arbeit zeigen wir mithilfe unterschiedlicher Zeitreihenanalysen, dass sich die Abhängigkeiten der Ausfallwahrscheinlichkeiten der dominanten CDS-Marktteilnehmer mit Einführung des zentralen Clearings moderat verringern. In der Gesamtschau zeigen die Ergebnisse eine potentiell stabilisierende Wirkung von CCPs für die Finanzmarktarchitektur von Derivatemärkten. Diese Wirkung hängt jedoch davon ab, welche Kontrakte von der CCP zum zentralen Clearing zugelassen werden. Risikoreiche Kontrakte profitieren besonders von der Möglichkeit des zentralen Clearings. Für CCPs sind jedoch insbesondere risikoarme, liquide Kontrakte mit hohen Handelsvolumina attraktiv, da diese den eigenen Umsatz maximieren bei geringeren Kosten für das Risikomanagement. Dies zeigt eindrücklich den Konflikt zwischen Regulatoren und Regulierten sowie die Notwendigkeit maßgeschneiderter Finanzmarktregulierung