????????? ??????-?????? ???????????? ?????? ?????? ????????? ?????????

Department of Energy Engineering (Battery Science and Technology)Aprotic electrolyte based lithium-oxygen batteries are of considerable interest due to its ultrahigh theoretical specific energy density (1675 mAh per gram of oxygen) against the present lithium-ion battery. In spite of the attractiveness of its high theoretical capacity, there is a number of drawbacks such as instability of electrochemical reaction of electrode and electrolytes. In order to overcome these parasitic reactions, significant efforts have been devoted to developing the key materials such as carbon-free air cathodes and high concentrated electrolytes. However, the CO2 evolution during the charging process and low ionic conductivity limit the ideal electrochemical reaction in aprotic electrolytes. In this thesis, we applied the molten electrolyte based on nitrate-based electrolyte (Li/Na/K/Cs/Ca-NO3). The molten electrolyte, which has a eutectic point of 65???, has the advantages of high stability and high-temperature operation, thereby preventing detrimental solvent byproducts in lithium-oxygen batteries. We examined the Oxygen Evolution Reaction (OER) and Oxygen Reduction Reaction (ORR) on operating temperature using in situ pressure drop and gas analyses, Differential Electrochemical Mass Spectrometry (DEMS). Our results demonstrated that the Li2O2, a discharge product, formed a stable hexagonal morphology in the lithium-oxygen battery upon discharge process by scanning electron microscopy and X-ray diffraction techniques. Also, it leads to improved oxygen mobility at high temperature since a molten salt was used as the electrolyte in lithium-oxygen batteries. In addition, we found that kinetics are improved with increasing operating temperature in molten salt electrolyte cells.ope

The summatory function of the M\"obius function in function fields

We study the growth rate of the summatory function of the M\"obius function in the context of an algebraic curve over a finite field. Our work shows a strong resemblance to its number field counterpart, which was proved by Ng in 2004. We find an expression for a bound of the summatory function, which becomes sharp when the zeta zeros of the curve satisfy a certain linear independence property. Extending a result of Kowalski in 2008, we prove that most curves in the family of universal hyperelliptic curves satisfy this property. Then, we consider a certain geometric average of such bound in this family, using Katz and Sarnak's reformulation of the equidistribution theorem of Deligne. Lastly, we study an asymptotic behavior of this average as the family gets larger by evaluating the average values of powers of characteristic polynomials of random unitary symplectic matrices.Comment: 16 pages. In this revision, an error in residue calculation in Section 2 is corrected, and a few bibliographic items are update

Owner challenges on major projects: The case of UK government

Many studies agree that owner organisations are important for successful project organising, but they tend to focus on particular aspects of project organising rather than providing a holistic analysis of owners as organisations. Our objective is to collect evidence of the full range of challenges public sector owners face in managing their major projects. After reviewing the literature on owner organisations, we carry out a case survey of 26 major projects to identify the principal challenges using a content analysis of UK National Audit Office Value for Money reports. Our original contribution is that the findings provide the first comprehensive picture of the full range of challenges of project organising faced by owner organisations. These findings push us theoretically to extend the scope of research in project organising to identify an extended core set of dynamic capabilities for project owner organisations to address these challenges

Labor Leading on Climate: A Policy Platform to Address Rising Inequality and Rising Sea Levels in New York State

With the renewed need for state action, this paper presents a case study of a labor-led initiative in New York State that seeks to address both economic inequality and the climate crisis. It discusses how organized labor, which has historically represented fossil fuel workers and has not been seen as a traditional climate ally, put forth a comprehensive climate jobs plan that could meaningfully reduce carbon emissions while also creating good, family-sustaining jobs to reduce income inequality. As the need for a broader coalition to advocate for sensible climate policy increases, this case study provides a road map for states across the country on how non-traditional allies can come together around a policy agenda that fights both inequality and climate change