Design Characteristics of the 224 kW Magdalen Islands VAWT

The evolution of the main design features of the Magdalen Islands vertical axis wind turbine (VAWT) is described. The turbine has a rotor height of 120 ft (36.58 m) and diameter 80 ft (24.38 m). It was operated as a joint project between NRC and Hydro-Quebec in grid-coupled mode from July 1977 to July 1978 when the rotor was destroyed in an accident. The accident, although unfortunate, tested the basic integrity of the design in a gross overspeed condition, and the rotor is being rebuilt with minor modifications. Some directions for future VAWT research are suggested

Design of an Adaptable Run-Time Reconfigurable Software-Defined Radio Processing Architecture

Processing power is a key technical challenge holding back the development of a high-performance software defined radio (SDR). Traditionally, SDR has utilized digital signal processors (DSPs), but increasingly complex algorithms, higher data rates, and multi-tasking needs have exceed the processing capabilities of modern DSPs. Reconfigurable computers, such as field-programmable gate arrays (FPGAs), are popular alternatives because of their performance gains over software for streaming data applications like SDR. However, FPGAs have not yet realized the ideal SDR because architectures have not fully utilized their partial reconfiguration (PR) capabilities to bring needed flexibility. A reconfigurable processor architecture is proposed that utilizes PR in reconfigurable computers to achieve a more sophisticated SDR. The proposed processor contains run-time swappable blocks whose parameters and interconnects are programmable. The architecture is analyzed for performance and flexibility and compared with available alternate technologies. For a sample QPSK algorithm, hardware performance gains of at least 44x are seen over modern desktop processors and DSPs while most of their flexibility and extensibility is maintained

Teaching And Assessing Ethics As A Learning Objective: One School's Journey

This paper reports the results of a ten-year effort to establish ethics as a learning objective for all business students, to assess the effectiveness in achieving that learning objective and to incorporate ethical conduct as a part of the school's organizational culture.  First, it addresses the importance of ethics instruction for all business students. Then curricular concerns are addressed, specifically the establishment of ethics as an overarching learning objective and ensuring adequate coverage of ethics throughout the curriculum.  Next, assessment mechanisms are described to demonstrate improvement in student's moral judgment and moral courage, in achieving the ethics learning objective using pre-tests and post-tests.  These tests validated the use of ethical vignettes/cases to improve ethical awareness and exposure and writing about moral exemplars to increase student resolve to have moral courage.  Finally, the paper addresses ways to measure and improve the ethical climate of the organization (faculty and students

Design of Tools for Press-countersinking or Dimpling 0.040-inch-thick-24S-T Sheet

A set of dimpling tools was designed for 0.040-inch 24S-T sheet and flush-type rivets 1/8 inch in diameter with 100 degree countersunk heads. The dimples produced under different conditions of pressure, sheet thickness, and drill diameter are presented as cross-sectional photographs magnified 20 times. The most satisfactory values for the dimpling tools were found to be: maximum punch diameter, 0.231 inch; maximum die diameter, 0.223 inch; maximum mandrel diameter, 0.128 inch; dimple angle, 100 degree; punch springback angle, 1 1/2 degree; and die springback angle, 2 degree

The Elastic Constants for Wrought Aluminum Alloys

There are several constants which have been devised as numerical representations of the behavior of metals under the action of loadings which stress the metal within the range of elastic action. Some of these constants, such as Young's modulus of elasticity in tension and compression, shearing modulus of elasticity, and Poisson's ratio, are regularly used in engineering calculations. Precise tests and experience indicate that these elastic constants are practically unaffected by many of the factors which influence the other mechanical properties of materials and that a few careful determinations under properly controlled conditions are more useful and reliable than many determinations made under less favorable conditions. It is the purpose of this paper to outline the methods employed by the Aluminum Research Laboratories for the determination of some of these elastic constants, to list the values that have been determined for some of the wrought aluminum alloys, and to indicate the variations in the values that may be expected for some of the commercial products of these alloys

Effect of Operating Conditions On Pressure Drop in A Pulse-Jet Cleaned Fabric Filter

A predictive model for pressure drop in a pulse-jet cleaned fabric filter and the effect of on-line vs. off-line pulse-jet cleaning on pressure drop were examined. Data were collected in experimentswith untreated polyester fabric and PTFE-laminated fabric. Twenty-four experimental conditions were studied in which each fabric repeatedly filtered limestone dust or flyash for 30, 120, or 480 s and was then cleaned either on-line or off-line. Each condition was replicated, resulting in a total of 48 experiments. Dust inlet concentration and superficial filtration velocity were maintained at 1.69 g m[-3] and 0.075 m s[-1] respectively. Based on conditions studied: 1) dust removal results from a complex interaction of the pulse pressure, pressure drop prior to pulsing, and dust areal density, w; 2) dust removal efficiency of a cleaning pulse, ε, increases as w increases, 3) the rate of increase in ε with w diminishes as w becomes larger; 4) the predictive model examined should be applied only if the dust areal density added during one filtration cycle, W[o], remains unchanged or if the rate of change in ε is small; 5) under some conditions off-line cleaning does not reduce pressure drop below that achieved by on-line cleaning; and 6) pressure drop depends primarily on fabric type and w[o].Master of Science in Environmental Engineerin

Takotsubo Syndrome: Uncovering Myths and Misconceptions

PURPOSE OF REVIEW Takotsubo syndrome (TTS) was described in Japan 3 decades ago to affect predominately postmenopausal women after emotional stress. This history is the basis of commonly held beliefs which may contribute to the underdiagnosis and misperception of TTS. RECENT FINDINGS TTS affects not only women, but can be present in both sexes, and can appear in children as well as in the elderly. TTS is characterized by unique clinical characteristics with morphological variants, and incurs a substantial risk for recurrent events and adverse outcomes. Physical triggers are more common than emotional triggers and are major disease determinants. TTS seems not to be completely transient as patients report ongoing chest pain, dyspnea, or fatigue even after months of the acute event. Knowledge of the clinical features and outcomes of TTS patients has evolved substantially over the past decades. The heterogeneous appearance of TTS needs to be recognized in all medical disciplines to maximize therapy and improve outcomes

Spontaneous Coronary Artery Dissection: A Rare Event?

Spontaneous coronary artery dissection is an infrequent cause of acute coronary syndrome with comparable clinical features. Previously considered a rare disease, recent scientific interest has revealed spontaneous coronary artery dissection as an important differential diagnosis of acute coronary syndrome, especially in young women, during pregnancy or postpartum, and in patients with fibromuscular dysplasia or other arteriopathies. However, there remain many uncertainties regarding pathophysiology, risk factors, acute treatment, and optimal long-term management. The aim of this review is to summarize current scientific evidence on epidemiology, management, and outcomes

Das Potential von Virtual Communities auf Basis von Distributed Virtual Environments für Kundengewinnung und -bindung

Zusammenfassung: 'In diesem Artikel soll der Einsatz von Distributed Virtual Environments (DVE) zur Bildung von Virtual Communities (VC) für kommerzielle Interessen untersucht werden. Nach der Charakterisierung von VC und DVE wird deren Symbiose zum Zweck der Kundengewinnung und -bindung im Consumer-Bereich untersucht. Dabei wird eine kritische Bewertung erster Prototypen und die Analyse der damit verbundenen technologischen, psychologisch-soziologischen und marketing-strategischen Probleme vorgenommen. Auf dieser Basis erfolgt abschließend die Diskussion eines Vorgehensmodells für den Aufbau DVE-basierter Gemeinschaften zur kommerziellen Nutzung und die Spezifikation eines Anforderungskataloges für erfolgreiche DVE in diesem Sektor