Infrared nanoscopy of Dirac plasmons at the graphene-SiO2 interface

We report on infrared (IR) nanoscopy of 2D plasmon excitations of Dirac fermions in graphene. This is achieved by confining mid-IR radiation at the apex of a nanoscale tip: an approach yielding two orders of magnitude increase in the value of in-plane component of incident wavevector q compared to free space propagation. At these high wavevectors, the Dirac plasmon is found to dramatically enhance the near-field interaction with mid-IR surface phonons of SiO2 substrate. Our data augmented by detailed modeling establish graphene as a new medium supporting plasmonic effects that can be controlled by gate voltage.Comment: 12 pages, 4 figure

Testing the Importance of Fixing Exogenously Some Parameters in Aggregate Modal Split Models, by means of Sensitivity Analysis.

Aggregate modal split (and distribution) models currently need exogenously determined values for such key parameters as the value of in-vehicle time, the value of waiting time and the car occupancy factor. Using hierarchical logit modal split models and data from the Garforth Corridor, to the east of Leeds, this paper set out to investigate the effects in the model aggrement to the data (and hence in its forecasting capabilities) of inputting different values for these parameters. 'To gain insight into the relative importance of each of these fixed parameters,the analytical point elasticities of the free parameters in the model with respect to them, were briefly examined. This exercise, together with some more practical post-hoc considerations led us to concentrate on the values of in-vehicle time and waiting time only. The rather surprising outcome of the analysis was that the model fits were not statistically different, for different values of the fixed parameters, their variation being accommodated by changes in the values of the free parameters. The main conclusion was that provided the exogeneous parameters are reasonably accurate they should produce models that are capable of performing as well (or badly) as models calibrated entirely from the data, and at a much lower cost

Valuation of Put Options on Leveraged Equity

This paper presents new closed form solutions for the valuation of European put options and of "down-an-in" barrier options written on leveraged equity. Unlike in past literature (Toft and Prucyk, 1997) and in keeping with empirical evidence, the model allows equity to retain value even after the firm's default and reorganisation. This stylised fact can significantly alter the valuation of equity put and "down-and-in" options as bankruptcy costs, bargaining power of equity holders, debt maturity and other firm parameters change. The value of "in-the-money" puts often decreases in the firm's assets volatility. The model can produce a variety of realistic implied equity volatility "skews".Equity put options; Leveraged equity; Default and reorganisation; Barrier options; "down-and-in" options

What Kenya’s street parliaments tell us about the value of in-person politics over online debates

The COVID-19 pandemic resulted in a reliance on more online political activity. New research in urban Kenya, however, which compares street-based and online political debate, shows the democratic value of continuing to invest in political debates that are face-to-face and informal

Commuting in small towns in rural areas: the case of St Andrews.

Since many rural commuters depend on the private car due to lack of convenient public transport, car reduction policies designed for large cities with ample public transport may be unsuitable for smaller towns. In particular, pricing policies designed to encourage public transport use may be less effective, as commuters with no convenient substitute to driving will be unable to switch. This paper develops multinomial and mixed logit models of commuters’ mode choice using data from a survey of commuters in the University of St Andrews. We find that the direct elasticities of the car mode are comparable to estimates reported in studies of commuting in larger urban areas, while the demand for public transport is considerably more elastic. The value of in-vehicle time is found to be about half of the UK average, reflecting that the roads in the St Andrews area are relatively uncongested.Mode choice, Rural commuting, Discrete choice models

Low-cost, multi-agent systems for planetary surface exploration

The use of off-the-shelf consumer electronics combined with top-down design methodologies have made small and inexpensive satellites, such as CubeSats, emerge as viable, low-cost and attractive space-based platforms that enable a range of new and exciting mission scenarios. In addition, to overcome some of the resource limitation issues encountered with these platforms, distributed architectures have emerged to enable complex tasks through the use of multiple low complexity units. The low-cost characteristics of such systems coupled with the distributed architecture allows for an increase in the size of the system beyond what would have been feasible with a monolithic system, hence widening the operational capabilities without significantly increasing the control complexity of the system. These ideas are not new for Earth orbiting devices, but excluding some distributed remote sensing architectures they are yet to be applied for the purpose of planetary exploration. Experience gained through large rovers demonstrates the value of in-situ exploration, which is however limited by the associated high-cost and risk. The loss of a rover can and has happened because of a number of possible failures: besides the hazards directly linked to the launch and journey to the target-body, hard landing and malfunctioning of parts are all threats to the success of the mission. To overcome these issues this paper introduces the concept of using off-the-shelf consumer electronics to deploy a low-cost multi-rover system for future planetary surface exploration. It is shown that such a system would significantly reduce the programmatic-risk of the mission (for example catastrophic failure of a single rover), while exploiting the inherent advantages of cooperative behaviour. These advantages are analysed with a particular emphasis put upon the guidance, navigation and control of such architectures using the method of artificial potential field. Laboratory tests on multi-agent robotic systems support the analysis. Principal features of the system are identified and the underlying advantages over a monolithic single-agent system highlighted

Calorimetry, activity, and micro-FTIR analysis of CO chemisorption, titration, and oxidation on supported Pt

The value of in situ analysis on CO chemisorption, titration and oxidation over supported Pt catalysts using calorimetry, catalytic and micro-FTIR methods is illustrated using silica- and titania-supported samples. Isothermal CO-O and O2-CO titrations have not been widely used on metal surfaces and may be complicated if some oxide supports are reduced by CO titrant. However, they can illuminate the kinetics of CO oxidation on metal/oxide catalysts since during such titrations all O and CO coverages are scanned as a function of time. There are clear advantages in following the rates of the catalyzed CO oxidation via calorimetry and gc-ms simultaneously. At lower temperatures the evidence they provide is complementary. CO oxidation and its catalysis of CO oxidation have been extensively studied with hysteresis and oscillations apparent, and the present results suggest the benefits of a combined approach. Silica support porosity may be important in defining activity-temperature hysteresis. FTIR microspectroscopy reveals the chemical heterogeneity of the catalytic surfaces used; it is interesting that the evidence with regard to the dominant CO surface species and their reactivities with regard to surface oxygen for present oxide-supported Pt are different from those seen on graphite-supported Pt

FIND THE VALUE OF IN USING TRIGONOMETRI THROUGH MATHEMATICS GAME OF TEN GRADE STUDENTS IN SMA NEGERI 1 AIR JOMAN

ABSTRACTDetermining a value of p is very important in mathematics. So, presented to find a value of p in using trigonometri through mathematics game of ten grade students in SMA Negeri 1 Air Joman. Actually, finding a value of p can be done through exterior and interior circle of poligon with trigonometry function. Poligon exterior circle consists of (1) the angles of the regular hexagon on a circle finding a value of p is  3, 141433159 or 3,14. (2) the angles of regular n sides on a circle finding a value of p is  3, 141592654 or 3,14. Poligon interior circle consists of (1) the regular hexagon whose sides tangent the circle finding a value of p is  3, 141911687 or 3,14. (2) the angles of regular n sides on a circle finding a value of p is  3, 141592654 or 3,14. The main problem is that people often say the value of p is irrational. But they can’t show why it is irrational. While in the students case, they don’t know the value of p clearly. So, the writer’s discovery from some references discussing the materials about how to find the value of p through exterior and interior circle of polygon with trigonometry function.Kata Kunci :  Poligon exterior circle, Poligon interior circle

A Study of the Development of Leadership Abilities in Teachers Through in-Service Education

It was the purpose of the writer to determine from research literature: (1) the value of in-service education programs in developing talent leadership in teachers, (2) the nature and origin of leadership, and (3) the teacher\u27s role in the in-service program

Approximating Pareto frontier using a hybrid line search approach

This is the post-print version of the final paper published in Information Sciences. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2010 Elsevier B.V.The aggregation of objectives in multiple criteria programming is one of the simplest and widely used approach. But it is well known that this technique sometimes fail in different aspects for determining the Pareto frontier. This paper proposes a new approach for multicriteria optimization, which aggregates the objective functions and uses a line search method in order to locate an approximate efficient point. Once the first Pareto solution is obtained, a simplified version of the former one is used in the context of Pareto dominance to obtain a set of efficient points, which will assure a thorough distribution of solutions on the Pareto frontier. In the current form, the proposed technique is well suitable for problems having multiple objectives (it is not limited to bi-objective problems) and require the functions to be continuous twice differentiable. In order to assess the effectiveness of this approach, some experiments were performed and compared with two recent well known population-based metaheuristics namely ParEGO and NSGA II. When compared to ParEGO and NSGA II, the proposed approach not only assures a better convergence to the Pareto frontier but also illustrates a good distribution of solutions. From a computational point of view, both stages of the line search converge within a short time (average about 150 ms for the first stage and about 20 ms for the second stage). Apart from this, the proposed technique is very simple, easy to implement and use to solve multiobjective problems.CNCSIS IDEI 2412, Romani