Preliminary investigation of high power microwave plasmas for electrothermal thruster use

Results are reported from preliminary tests to evaluate the high power microwave electrothermal thruster (MET) concept, which employs a free-floating plasma discharge maintained by applied CW microwave power to heat a propellant gas flow. Stable plasmas have been created and maintained in helium (He), nitrogen (N2), and hydrogen (H2) as propellants in both the TM(sub 011) and TM(sub 012) modes at discharge pressures from 10 Pa to 69 kPa. Reproducible starting conditions of pressure and power have been documented for all the plasmas. Vortical inflow of the propellant gas was observed to cause the formation of on-axis 'spike' plasmas. The formation and unformation conditions of these plasmas were studied. Operation in the spike plasma condition enables maximum power absorption with minimum wall heating and offers maximum efficiency in heating the propellant gas. In the spike condition, plasmas of the three propellant gases were investigated in an open channel configuration to a maximum applied power level of 11.2 kW (in N2). Microwave power coupling efficiencies of over 90 percent were routinely obtained at absorbed power levels up to 2 kW. Magnetic nozzle effects were investigated with a superconducting solenoid Al magnet applying a high magnetic field to the plasmas in and exiting from the discharge tube

Using Big Data for Analytics and Decision Support

People and the computers they use are generating large amounts of varied data. The phenomenon of capturing and trying to use all of the semi-structured and unstructured data has been called by vendors and bloggers Big Data . Organizations can capture and store data of many types from almost any source, but capturing and storing data only adds value when it has a useful purpose. Big Data must be used to provide input to analytics and decision support capabilities if it is to create real value for organizations. Some bloggers, industry leaders and academics have become disillusioned by the term Big Data. It is a marketing term and not a technical term. More descriptive terms like unstructured data, process data and machine data are more useful for IT professionals. Researchers need to study and document use cases that explain how specific, novel data, so-called Big Data, can be used to support decision-making

Specifying An Expanded Framework for Classifying and DescribingDecision Support Systems

This article defines an expanded conceptual framework for classifying and describing Decision Support Systems (DSS) that consists of one primary dimension and three secondary dimensions. The primary dimension is the dominant technology component or driver of decision support. The three secondary dimensions are the targeted users, the specific purpose of the system and the primary deployment or enabling technology. Five generic DSS types are identified and defined based upon the dominant technology component, including Communications-driven, Data-driven, Document-driven, Knowledge-driven, and Model-driven Decision Support Systems. Specific targeted users like individuals, groups, or customers can use any of the five generic types of DSS. Also, a DSS can be created for a decision- specific or a more general purpose. Finally, in the framework, the DSS deployment and enabling technology may be a mainframe computer, a client/server LAN, a spreadsheet or a web-based technology architecture. The goal in defining an expanded DSS framework is to help researchers better identify meaningful, homogeneous categories for research and to help Information Systems professionals describe and explain the various types of decision support systems

The IS Core-II: The Maturing IS Discipline: Institutionalizing our Domain of Inquiry

Even though computerized information systems are a relatively recent phenomenon that continues to evolve, these technology-based systems are now studied by a maturing academic discipline. This article examines the issue of Information Systems (IS) core concepts; explores the content and boundaries of the Information Systems research domain; and discusses whether consensus about an identity and domain for Information Systems is important and worth discussing. Despite concerns in the profession about an IS identity crisis, Information Systems is a legitimate area of scientific research and inquiry. Groups like the Association for Information Systems are institutionalizing the IS domain of inquiry. Furthermore, Information Systems researchers are becoming much more assertive about the importance of the IS research domain

Acquiring Small and Medium-Sized Companies: A Study of Corporate Decision Behavior

This field research study investigated corporate acquisition decisions made by managers in U.S. manufacturing and conglomerate firms. The introductory chapters review organizational decision theories and empirical research on organizational and acquisition decision making. The thesis presents and investigates hypotheses for two descriptive models: a prediction model and a decision-process model. Through mail questionnaires, data were gathered about 28 acquisitions completed between October 1, 1979 and March 31, 1980. Managers were asked for retrospective information about decision activities and for a current assessment of the acquired company\u27s performance . Twenty-six companies made the acquisitions: nine very large companies with 1979 sales of more than $450 million and seventeen smaller companies. Of the 28 acquired companies, 14 had 1979 sales of$1 to $10 million, 13 had sales of$10 to $35 million, and one had sales of more than$350 million. The results of correlation and regression analyses indicate that moderate levels of participation in acquisition subdecisions and direct contact with the prospect are related to successful acquisitions, but higher levels of both activities are related to lower levels of success. Also, increased participation did not increase the perceived effectiveness of implementation activities. The amount of formal analytical activity and CEO involvement are not related to successful acquisitions. CEO involvement seems to depend on the size of the acquiring company, with CEOs in smaller companies more involved in making small and medium-sized acquisitions. Managers use more complex and extensive decision processes when an unrelated business is investigated, but the process is apparently often ineffective. Firms that had made more acquisitions also had different decision processes, including lower levels of participation and less use of information sources. Both experience making acquisitions and acquiring a related business are good predictors of a successful acquisition. Finally, a planned search for prospects is not related to more successful acquisitions. Only initiation by an unusual source alters the decision process, and then more CEO involvement and intensive search occur

Web-Based and Model-Driven Decision Support Systems: Concepts and Issues

New technologies, especially the World-Wide Web technologies, have created many opportunities for research about Decision Support Systems. This paper reviews key concepts and technical issues. The technology of DSS is evolving rapidly and academic researchers need to catch-up with practitioners who are implementing innovative DSS. The paper briefly mentions a number of Web sites with innovative DSS that highlight current developments. Much remains however to be investigated and studied if DSS are to contribute to a company’s success

A History of Microcomputer Spreadsheets

In 1978, the first microcomputer spreadsheet program was developed. Since then spreadsheets have become widely used as productivity software for business and home computer users. Many of today\u27s MIS faculty members use a variety of spreadsheet programs, but the origins and evolution of this product category is of on-going interest to students, managers and MIS faculty. This article is a contemporary history of microcomputer spreadsheets based on primary and secondary sources

Issues in Designing and Using Web-based Teaching Cases,

This paper examines the possibilities and problems associated with designing and using web-based teaching cases in business courses. Six types of web-based cases are discussed, including (1) a traditional linear case with no hyperlinks; (2) a traditional linear case with hyperlinks; (3) a non-linear case; (4) an unstructured “live” case; (5) a “timeline” case; and (6) a case with contingent branching. Web cases can be more dynamic and “richer” in detail than static printed cases. However, designing and developing such cases can involve new challenges and problems, including mastering technical skills; considering the effect of the hyperdocument on reader comprehension; and maintaining a dynamic case study