Historical development of the windmill

Throughout history, windmill technology represented the highest levels of development in those technical fields now referred to as mechanical engineering, civil engineering, and aerodynamics. Key stages are described in the technical development of windmills as prime movers; from antiquity to construction of the well known Smith-Putnam wind turbine generator of the 1940's, which laid the foundation for modern wind turbines. Subjects covered are windmills in ancient times; the vertical axis Persian windmill; the horizontal axis European windmill (including both post mills and tower mills); technology improvements in sails, controls, and analysis; the American farm windmill; the transition from windmills to wind turbines for generating electricity at the end of the 19th century; and wind turbine development in the first half of the 20th century

Wide angle Michelson Doppler imaging interferometer

The optical system, stepping control, phase and modulation depth, array detector, and directions sensor are described for a specialized type of Michelson interferometer which works at sufficiently high resolution to measure the line widths and Doppler shifts of naturally occurring atmospheric emissions. With its imaging capability, the instrument can potentially supply this data independently for each element of the 100 x 100 detector array. The experiment seeks: (1) to obtain vertical profiles of atmospheric winds and temperatures as functions of latitude by observing near the limb; (2) to acquire exploratory wind and temperature data on smaller scale structures in airglow irregularities and in auroral forms; and (3) to collaborate with other Spacelab experiments, such as barium cloud releases, in providing wind and temperature data

Wind turbine acoustic standards

A program is being conducted to develop noise standards for wind turbines which minimize annoyance and which can be used to design specifications. The approach consists of presenting wind turbine noise stimuli to test subjects in a laboratory listening chamber. The responses of the subjects are recorded for a range of stimuli which encompass the designs, operating conditions, and ambient noise levels of current and future installations. Results to date have established the threshold of detectability for a range of impulsive stimuli of the type associated with blade/tower wake interactions. The status of the ongoing psychoacoustic tests, the subjective data, and the approach to the development of acoustic criteria/standards are described

Bi-Directional Relativistic Jets of the Radio Galaxy 1946+708: Constraints on the Hubble Constant

We present measurements of bi-directional motions in the jets of the radio galaxy 1946+708 at z=0.101. This is a Compact Symmetric Object with striking S-symmetry. Sensitive 15 GHz observations reveal a compact component at the center of symmetry with a strongly inverted spectrum, that we identify as the core. From five 4.9 GHz observations spread over 4 years we have determined the velocities of four compact jet components. If simple kinematic models can be applied then the inclination of the source and the bulk jet velocity can be directly determined for any assumed value of the Hubble constant. Conversely, the measurements already place constraints on the Hubble constant, and we show how further observations of 1946+708 can yield an increasingly accurate determination of H_0.Comment: in press at ApJ Letters, 12 page LaTex document includes 5 postscript figure

WAMDII observation of an auroral atmosphere wave event

Field tests of WAMDII (Wide Angle Michelson Doppler Imaging Interferometer) on February 23 to 24, 1984 in Saskatoon produced wind images of the aurora that show well defined wave structures in lambda 5577. Wavelengths and velocities of these structures suggest an acoustic-gravity wave interpretation, but their short duration warrants their being termed an event. The Dopplergrams are presented with emphasis on the interpretation of the waves and a discussion of possible sources

Should I Stay or Should I go? Founder Power and Exit via Initial Public Offering

Founders can voluntarily exit their ventures via initial public offerings (IPOs). In this study, we build on power theory to develop and test a model of founder exit using a dataset of 313 founders from 177 entrepreneurial IPOs between 2002 and 2010. We largely find support for the model—a negative relationship between founder power and full exit. To capture the underlying mechanism of the power-exit relationship, we conducted two experiments in which we randomly assigned decision makers to either a high- or low-power condition. We find that decision makers in the low-power condition are more likely to use a full exit via IPO than those in the high-power condition and that frustration mediates this relationship. However, founders can also engage in partial exits, including a managerial partial exit in which the founder leaves management but keeps ownership and a financial partial exit in which the founder divests ownership but remains in management. We find that the negative relationship between founder power and exit is more negative for full exits than partial exits. With this paper, we contribute to the literature on exit by identifying a novel mechanism—frustration—underlying power’s influence on the likelihood and type of founder exit

Data Analytics

This chapter sets out to illustrate the dictum that there is (almost) nothing new under the sun. More specifically, its goal is to make the unfamiliar familiar within the field of data analytics. The need for such a treatment can be gauged from the plethora of terms currently vying for attention in the contemporary data analysis landscape, which can be puzzling even for seasoned researchers. These terms include: data mining, data science, data analytics, machine learning, deep learning, neural networks, and artificial intelligence. Hybrid terms such as ‘big data analytics’ are also emerging. As for the current front-runner term, data analytics, the evidence provided by the number of search engine hits reveals multiple competing versions subdivided by application domains, ranging from business analytics and crime analytics, to performance analytics, visual analytics, and many more. There is also an emerging software sub-industry providing tools for data analytics, many of which are named after the company which originally developed them

Improving the capabilities and use of strategic decision making tools.

Recent research has shown that a substantial proportion of local authorities do not use models for strategy formulation or scheme design and appraisal. Models were perceived to be unable to reflect the range of policy instruments which local authorities now use; and were seen as too complex for local authority staff and stakeholders to use themselves. To overcome these issues the MARS model has been enhanced to provide a transparent and easy to use tool with a flight simulator front-end. This paper describes the model along with improvements to the representation of public transport by inclusion of quality and crowding factors and the incorporation of urban heavy rail