An Efficient Computation of Coherent Synchrotron Radiation in a Rectangular Chamber, Applied to Resistive Wall Heating

We study coherent synchrotron radiation (CSR) in a perfectly conducting vacuum chamber of rectangular cross section, in a formalism allowing an arbitrary sequence of bends and straight sections. We apply the paraxial method in the frequency domain, with a Fourier development in the vertical coordinate but with no other mode expansions. A line charge source is handled numerically by a new method that rids the equations of singularities through a change of dependent variable. The resulting algorithm is fast compared to earlier methods, works for short bunches with complicated structure, and yields all six field components at any space-time point. As an example we compute the tangential magnetic field at the walls. From that one can make a perturbative treatment of the Poynting flux to estimate the energy deposited in resistive walls. The calculation was motivated by a design issue for LCLS-II, the question of how much wall heating from CSR occurs in the last bend of a bunch compressor and the following straight section. Working with a realistic longitudinal bunch form of r.m.s. length $10.4~\mu$m and a charge of 100 pC we conclude that the radiated power is quite small (28 W at a 1 MHz repetition rate), and all radiated energy is absorbed in the walls within 7 m along the straight section.Comment: 47 pages, 24 figure

An examination of ongoing trends in airline ancillary revenues

The airline industry seems permanently embedded in producing thin margins and continuously combatting downward pressure on yields. To perpetuate the problem, the industry remains eclipsed with high cost structures and low barriers to entry. However, a new sizzling concept continues to counterbalance these effects in the form of ancillary revenues. Globally, these revenues have increased by 121% from 2010 to 2014 – and the trend is set to continue as carriers are quickly implementing structural changes to accommodate these revenues streams. This paper examines the performance of the two core classifications of ancillary revenues, which are unbundled products and commission based income. It also investigates the willingness of passengers to pay for these services together with what type of ancillary items are acceptable at a particular price point. The study found that passengers value a narrow range of perceived ‘necessity’ products and services such as food and drink, checked baggage and seat assignment as opposed to perceived ‘optional’ unbundled or commission based products/services. It also found significant differences in WTP for specific ancillary services based on carrier type (FSC/LCC/Charter), length of flight (long and short haul) and journey purpose (business, leisure, VFR)

An evaluation of Nigerian ports post-concession performance

Purpose: The quest for efficiency is claimed to be the major objective of port privatisation and this has led many ports in Africa to undertake port reforms. Based on this, Nigerian ports were concessioned and operations were handed over in one scoop to private operators between 2006 and 2007. This paper is looking to investigate in the reform that took place in a very short period of time improved the performance of Nigerian ports. This paper is also looking to provide a model for future evaluation. Research Approach: A window based DEA model with panel data will be employed to measure pre- and post concession Nigerian ports' performance to determine efficiency gains from port reform. Secondly, to demonstrate how concession influence efficiency, a DEA based Malmquist productivity Insex will be used to determine the sources of (in)efficiency by decomposing the efficiency into frontier shift effects and catch-up effects. Findings and Originality: The results revealed that none of the ports is hundred percent efficient before and after concession but rather a tremendous increase in throughput and ship traffic after the reform in most of the ports. Apapa port is the most efficient while Calabar and Warri are inefficient although there were fluctuations in efficiency in all the ports. The research is inconclusive because it is still ongoing Although some studies have investigated the relationship between port efficiency and privatisation however several gaps still exist as the studies are skewed in favour of container ports in the developed world, mainly in Europe. Therefore, the need arises to critically look at the overall efficiency of national port system to enhance the efficiency of global transport chain. Research Impact: The study will contribute to existing literature on port performance being the first to evaluate the post concession performance of a major maritime player in Sub-Saharan Africa. It will contribute to the never- ending debate by the Academia on the effect of ownership or privatisation on efficiency from the perspective of port institutional reforms in the third world countries Practical Impact: It will benefit the Federal Government of Nigeria as a reference document of the first five years of the port reform policy and help the Government to intervene in areas of observed inefficiencies and make adjustments where possible. On the part of the "Landlord" NPA it will help them in the performing their regulatory role by identifying the operators who are making inefficient use of the resources allocated to them and provide the basis for future evaluation. Finally, it will give the various stake holders in the Maritime Industry a full grasp of the effect of concession in a Nation's port as Nigeria is the first country in the world to hand over terminal operations in all her ports in one scoop

Detailed pseudo-static drive train modelling with generator short circuit

Drivetrain failures contribute significantly to wind turbine downtime. Although the root causes of these failures are not yet fully understood, transient events are regarded as an important contributory factor. Despite extensive drive train modelling, limited work has been carried out to assess the impact of a generator short circuit on the drivetrain. In most cases, a generator short circuit is classed as a failure in itself with minimal focus on the subsequent effects on the gearbox and other drivetrain components. This paper will look to analyse the loading on the drivetrain for a doubly fed induction generator (DFIG) short circuit event with turbine ride through using a combination of Simulink, Garrad Hassan’s Bladed and RomaxWind drive train modelling software

A review of commercial air policies: Identifying the gaps

Commercial Air Service Agreements remain the overwhelming focus when it comes to assessing the degree of liberalisation and deregulation in air transport markets. If individual countries are assessed for levels of traffic growth, competition and overall competitiveness, it becomes clear that there is a wide range of policy levers that can restrict markets but go way beyond the realms of official Air Service Agreements. This study provides a fresh holistic view of policy barriers restricting growth in world air transport markets by assessing non-ASA policies affecting the airline sector directly as well as levels of (de)regulation in the related airport sector. A selection of case countries provides evidence that if traffic growth, competition and resultant consumer welfare as a result of overall competitiveness are the objective functions of policy-makers, it is advisable for states to create much more comprehensive commercial air policy frameworks and more holistic measures/indices by which to benchmark levels of policy ‘liberalness’

Look at Me Now: What Attracts U.S. Shareholders?

This paper investigates the underlying determinants of home bias using a comprehensive data set on U.S. investors' aggregate holdings of every foreign stock. Among those foreign stocks that are not listed on U.S. exchanges, which account for more than 96 percent of our usable data sample, we find that U.S. investors prefer firms with characteristics associated with greater information transparency, such as stronger home-country accounting standards. We document that a U.S. cross-listing is economically important, as U.S. ownership of a foreign firm roughly doubles upon cross-listing in the United States. We explore the cross-sectional variation in this "cross-listing effect" and find that the increase in U.S. investment is greatest for firms that are from weak accounting backgrounds and are otherwise informationally opaque, suggesting that the key effect of cross-listing is improvements in disclosure that are valued by U.S. investors. By contrast, cross-listing does not increase the appeal of stocks from countries with weak shareholder rights, suggesting that U.S. cross-listing cannot substitute for legal protections in the home country. Nor does the cross-listing effect appear to be driven simply by increased "familiarity"� with the stock or lowered cross-border transactions costs.

U.S. International Equity Investment

U.S. investors are the largest group of international equity investors in the world, but to date conclusive evidence on which types of foreign firms are able to attract U.S. investment is not available. Using a comprehensive dataset of all U.S. investment in foreign equities, we find that the single most important determinant of the amount of U.S. investment a foreign firm receives is whether the firm cross-lists on a U.S. exchange. Correcting for selection biases, cross-listing leads to a doubling (or more) in U.S. investment, an impact greater than all other factors combined. We also show that our firm-level analysis has implications for country-level studies, suggesting that research investigating equity investment patterns at the country-level should include cross-listing as an endogenous control variable. We describe easy-to-implement methods for including the importance of cross-listing at the country level.

Opportunities for Producing Table Grapes in Egypt for the Export Market: A Decision Case Study

The Barakat Fruit Farm desires to increase their share of the exportable grape market in Egypt. Unfortunately, the grape cultivars currently cultivated by the farm bear fruit after the early market window to the European Union when prices are high. An analysis of the company, competition, consumer, market channel, and conditions, provides insight into possible solutions to the challenges faced by the farm management. Designed for undergraduate classroom use, this case encourages students to think outside of traditional production techniques to arrive at solutions that are viable from both crop culture and financial standpoints.Decision case, horticulture, agriculture economics, grape production, Production Economics, Teaching/Communication/Extension/Profession, Q10, Q11,

Processed Chili Peppers for Export Markets: A Capital Budgeting Study on the AgroFood Company

The AgroFood Company, which currently exports fresh chili peppers to European clients, desires to expand the product mix offered. The company, as it expands its production of fresh peppers for export, has an increasing supply of grade 2 peppers that are unmarketable in Egypt. However, an attractive market for processed frozen chili peppers exists in Europe. To expand their client base, capitalize on a value added product, and minimize product waste, the AgroFood Company desires to develop processing practices for chili peppers produced in Egypt. The AgroFood Company would like to identify its options in the processed pepper market. An analysis of the company, competition, consumer, market channel, and conditions, provides insight into possible solutions to the challenges faced by the farm management. Designed for undergraduate classroom use, this case will provide students with an opportunity to evaluate the merits of business expansion into a high capacity, automated mechanical processing facility for grade 2 vegetables.Decision case, horticulture, agriculture economics, chili pepper production, protected vegetable production, Crop Production/Industries, Food Security and Poverty, Production Economics,