What drives diesel fuel prices?

Historically, gasoline has commanded a premium over diesel, but that changed in mid-to-late 2007, when diesel rose above gasoline. In 2007 and 2008, however, gasoline traded higher than diesel only 21.1 percent of the time. This deviation from historic norms raises an interesting question--what drives diesel prices? As with virtually all petroleum-derived products, the story begins with oil prices. Seasonal patterns also play a significant role. Demand for a range of oil-based products changes with the weather, and prices fluctuate as refiners adjust their output mix. Government regulations are another source of price variability. Earlier this decade, new standards aimed at reducing diesel fuel's sulfur content required further processing that increased refinery costs and prices for consumers. Finally, short-term changes in supply and demand--including imports--factor into pricing on a day-to-day basis. Our model suggests that spot diesel should rise 25 cents a gallon over the next six months and 41 cents a gallon over the next 18 months.Petroleum products - Prices ; Petroleum industry and trade ; Energy consumption ; Econometric models

A natural formation scenario for misaligned and short-period eccentric extrasolar planets

Recent discoveries of strongly misaligned transiting exoplanets pose a challenge to the established planet formation theory which assumes planetary systems to form and evolve in isolation. However, the fact that the majority of stars actually do form in star clusters raises the question how isolated forming planetary systems really are. Besides radiative and tidal forces the presence of dense gas aggregates in star-forming regions are potential sources for perturbations to protoplanetary discs or systems. Here we show that subsequent capture of gas from large extended accretion envelopes onto a passing star with a typical circumstellar disc can tilt the disc plane to retrograde orientation, naturally explaining the formation of strongly inclined planetary systems. Furthermore, the inner disc regions may become denser, and thus more prone to speedy coagulation and planet formation. Pre-existing planetary systems are compressed by gas inflows leading to a natural occurrence of close-in misaligned hot Jupiters and short-period eccentric planets. The likelihood of such events mainly depends on the gas content of the cluster and is thus expected to be highest in the youngest star clusters.Comment: 7 pages, 4 figures. Accepted for publication in MNRAS. Updated to match published versio

Perspektiven zur Kombination von automatischem Animationsdesign und planbasierter Hilfe

Aktuelle Themen auf dem Gebiet der intelligenten Benutzerschnittstellen behandeln derzeit die automatische Planung multimodaler Präsentationen. Hierbei stand bisher im wesentlichen die koordinierte Generierung von Text und Graphik im Vordergrund. In Zukunft wird hier aufgrund der Komplexität der zu präsentierenden Information zunehmend auch die Einbeziehung realistischer animierter 3D-Graphiken gefordert sein. Einen anderen wichtigen Forschungsschwerpunkt bildet der Einsatz graphischer Ausgabekomponenten für planbasierte Hilfesysteme. Die vorliegende Arbeit hat zum Ziel zunächst einen Überblick über den derzeitigen Stand der Forschung in diesen beiden Bereichen zu geben, als auch neue Anforderungen an die automatische Animationsgenerierung und an Systeme zur planbasierten graphischen Hilfe zu formulieren. Anschließend wollen wir, basierend auf Ergebnissen und Erfahrungen aus WIP und PLUS, Perspektiven für eine mögliche Weiterentwicklung und Integration von Techniken der Animationsplanung und graphischen Hilfe präsentieren

Planbasierte graphische Hilfe in objektorientierten Benutzungsoberflächen

Wir stellen das System PLUS vor, ein planbasiertes graphisches Hilfesystem für Applikationen mit einer objektorientierten Benutzerschnittstelle. Es werden die Hilfekomponente InCome+, die Animationskomponente und der graphik-orientierte Planeditor PlanEdit+ beschrieben. PlanEdit+ ermöglicht den interaktiven Aufbau der hierarchischen Planbasis, die die Grundlage für den Planerkennungsprozeß bildet.Eine zentrale Komponente der graphischen Hilfe in unserem System stellt das Modul InCome+ dar, das den Interaktionskontext des Benutzers visualisiert und darüberhinaus weitere Features wie semantische Undo- und Redo-Möglichkeiten und einen kontext-sensitiven Tutor zur Verfügung stellt. Als wesentliche Erweiterung der graphischen Benutzerunterstützung wird innerhalb von PLUS die Präsentation animierter Hilfe integriert. Es werden Benutzeraktionen simuliert, indem eine Animation über die aktuelle Benutzerschnittstelle gelagert wird. Die Animationssequenz wird im Kontext der aktuell vom Benutzer verfolgten Aufgabe generiert

Temperature effects on the magnetization of quasi-one-dimensional Peierls distorted materials

It is shown that temperature acts to disrupt the magnetization of Peierls distorted quasi-one-dimensional materials (Q1DM). The mean-field finite temperature phase diagram for the field theory model employed is obtained by considering both homogeneous and inhomogeneous condensates. The tricritical points of the second order transition lines of the gap parameter and magnetization are explicitly calculated. It is also shown that in the absence of an external static magnetic field the magnetization is always zero, at any temperature. As expected, temperature does not induce any magnetization effect on Peierls distorted Q1DM.Comment: 11 pages, 2 figure

Multi-Objective Optimization of Mooring Systems for Offshore Renewable Energy

This is the author accepted manuscript. The final version is available from EWTEC via the link in this record.This paper presents a method for the optimization of mooring systems in offshore renewable energy systems. This methodology considers the location of anchors as well as the length, material, and diameter of the mooring lines in order to simultaneously minimize the tension in the lines, the cost of the mooring system, and the fatigue damage in the system. By considering these three objectives using a multi-objective approach rather than reduction to a single objective optimization problem allows a Pareto hull of solutions to be obtained representing a range of solutions which balance the three objectives. From this, a system designer can select the design which appropriately balances the trade-off between the competing objectives. In this work, a set of mooring designs that represent efficient solutions for the constraints are found and presented considering the OC4 DeepCWind semi-submersible at Wave Hub. This reliability-based design optimization approach will be applicable to other offshore technology subsystems allowing reliability to be considered in a multi-objective optimization from the design phase.This work is funded by the EPSRC (UK) grant for the United Kingdom Centre for Marine Energy Research (UKCMER) [grant number: EP/P008682/1]

The effect of transnational threats on the security of Persian Gulf maritime petroleum transportation

Today\u27s interconnected economy is dependent on petroleum products as a principal component of the energy mix and a critical element in global infrastructures. With the escalating demand for oil and natural gas, the world relies heavily on maritime transportation to move 62 % of world trade on fixed routes. The Persian Gulf countries are crucial because about 88 % of oil exports pass through the Strait of Hormuz. The Strait is strategically located between Iran and Oman, where 20 million barrels of crude oil per day is carried by supertankers. These shipments account for 40 % of seaborne oil traded worldwide. According to the Energy Information Administration, due to increasing demand this region will require 2. 5 times more tankers than are in existence today to meet demand by 2025. Nevertheless, the persistent, expanding, and increasingly sophisticated physical attacks against maritime transportation present an alarming pattern. The focus of this article is three fold. First, to explain major transnational threats within the context of piracy and terrorism. Second, to present the costs and the economic impacts of piracy and terrorism on international trade. Third, to point out the main contributing factors involved in the increase in the number of attacks on maritime petroleum transportation vessels. Given the strategic importance of the Persian Gulf countries, due to their petroleum contributions to the world, this paper focuses on the maritime flows of petroleum from this region through navigation courses to Asia, the United States, and Europe. © 2012 Springer Science+Business Media, LLC

The Opportunity Costs of Large-Deck Carriers: Naval Strategy for the 1990sand Beyond

As a nation of travelers and traders, naval power has long played a central role in the defense of American interests abroad. The oceans bordering North America have been both a barrier and a highway, separating the United States from potential enemies, connecting it to allies, and providing a venue for commerce and trade . Geography dictated the prominent role of naval forces in American foreign policy during the eighteenth and nineteenth centuries, and with the emergence of the United States as a military and economic superpower, Americans have come to depend even more heavily on naval forces as foreign policy instruments

Parathyroid localization

Twenty-nine consecutive patients with suspected primary hyperparathyroidism were examined preoperatively using ultrasound, sonographically guided fine needle aspiration, and aspirate immunostaining for PTH. In 25 patients, localization of enlarged parathyroid glands was successful. In 2 patients, the tumors were located retrosternally and, thus, could not be detected by ultrasound. One patient had a multinodular goiter which impeded localization. In 1 patient with renal osteodystrophy, 2 enlarged parathyroid glands in the neck were not visualized preoperatively. Cytology was not diagnostic, although some cytological features were suggestive of parathyroid cells. Immunostaining of the aspirated smears for PTH, however, correctly diagnosed all preoperatively localized lesions. Ultrasound should be the routine procedure of choice for preoperative localization of abnormal parathyroid glands in primary hyperparathyroidism. Fine needle aspiration and immunocytochemistry can supply confirmation, if necessary