The formation number of vortex rings formed in uniform background co-flow

The formation of vortex rings generated by an impulsively started jet in the presence of uniform background co-flow is studied experimentally to extend previous results. A piston–cylinder mechanism is used to generate the vortex rings and the co-flow is supplied through a transparent shroud surrounding the cylinder. Digital particle image velocimetry (DPIV) is used to measure the development of the ring vorticity and its eventual pinch off from the generating jet for ratios of the co-flow to jet velocity ($R_{v})$ in the range 0 – 0.85. The formation time scale for the ring to obtain maximal circulation and pinch off from the generating jet, called the formation number ($F$), is determined as a function of $R_{v}$ using DPIV measurements of circulation and a generalized definition of dimensionless discharge time or ‘formation time’. Both simultaneous initiation and delayed initiation of co-flow are considered. In all cases, a sharp drop in $F$ (taking place over a range of 0.1 in $R_{v}$) is centred around a critical velocity ratio ($R_{crit}$). As the initiation of co-flow was delayed, the magnitude of the drop in $F$ and the value of $R_{crit}$ decreased. A kinematic model based on the relative velocities of the forming ring and jet shear layer is formulated and correctly predicts vortex ring pinch off for $R_{v} \,{>}\, R_{crit}$. The results of the model indicate the reduction in $F$ at large $R_{v}$ is directly related to the increased convective velocity provided to the ring by the co-flow

Vortex ring pinchoff in the presence of simultaneously initiated uniform background co-flow

Vortex rings were formed with a piston-cylinder mechanism in the presence of uniform background co-flow supplied through a shroud surrounding the cylinder. The jet and co-flow were started simultaneously. Ratios of the co-flow to jet velocity (Rv) in the range 0–1 were considered. The formation number (F) as a function of Rv was determined using the procedure of Gharib et al. [J. Fluid Mech. 360, 121 (1998)] and a generalized definition of formation time. The results show a sharp decrease in F as Rv increases from 0.5–0.75, suggesting possible performance limitations for pulsed-jet propulsion

What is missing from ISO 9000 international quality standards training in the United States?

Carnevale, Gainer and Villet (1991) observed that employers have too often used training approaches that failed to deliver “new knowledge in a context meaningful to the learner.” This conclusion was consistent with the results found in a recent study of 406 United States companies that used training to prepare their employees for registration to the ISO 9000 series of international quality assurance standards. The vast majority of companies failed to address employee learning needs, and used few research-based instructional strategies to enhance training transfer from workshop to shop floor. Companies rarely grouped employees by their ability to learn and infrequently used the instructional strategies of analogies, behavioral objectives, imagery, and practice and feedback. More startling than the lackluster use of these instructional strategies were the results obtained for management commitment. Although workforce training was required by the ISO 9000 standards, and failure to meet this requirement would threaten the quality registration status of companies, there was a general lack of management commitment to training found in this nationwide survey. This paper is important because it reveals many shortcomings of training practices by companies engaged in international trade and registered to the ISO 9000 standards. Furthermore, it suggests that grouping employees by their ability to learn may function to enhance the implementation of instructional strategies in such a way as to improve training transfer and reduce nonconformances against the international standards

Under One Roof: A Theology of Mercy Responding to Tragic Flooding in Minot, North Dakota

God’s people can play a critical role in times of natural disaster. This ministry paper explores the theological concepts that propel a local church to action during a time of natural disaster. In addition, this paper will provide a practical framework for a local church to respond with incarnational ministry that transforms disaster-related human suffering with the tangible compassion of Christ. Following a 2011 Level 1 natural disaster, Our Savior Lutheran Church in Minot, North Dakota, coordinated a ministry of mercy where five thousand volunteers from forty-two states changed the city’s trajectory through Christian service. Often churches do not know the transformational role they can play in the event of a disaster. This paper offers a framework to provide transformational mercy during such a time. This paper contains three sections. The first section explores the city of Minot and Our Savior Lutheran Church and discusses how pre-disaster relationships set the stage for transformational ministry. This section then highlights the pivotal role local congregations can play in healing a disaster-ridden community through the tangible compassion of Christ. The second section examines theological concepts that propelled a church to action when confronted with human suffering. This section reviews seven books that discuss the church’s role in incarnational mercy care and develops a theology of incarnational disaster response through mercy and mission. The third section provides a practical framework for a local congregation to engage in incarnational disaster response with the introduction of a disaster response handbook. The handbook raises a vision for service following a local disaster and exposes church leaders to multi-faceted opportunities for incarnational mercy care within their community. A plan for implementation is also offered

Status Inconsistent Entrepreneurs and Robert Merton\u27s Innovation

From where springs forth entrepreneurs? The United States is experiencing an unprecedented increase of entrepreneurs. They have emerged in growing numbers during the past ten to fifteen years (Drucker, 1985), reaching a crescendo in what American Demographics has called the Entrepreneurial Eighties (Russell, 1985). Los Angeles Mayor Tom Bradley recently recognized this occurrence by declaring an Entrepreneur Day for his city at the annual meeting of the Young Entrepreneurs Organization (Givens and Goldberg, 1986). What is an entrepreneur? There have been many definitions since the term was coined by French economist J. B. Say in about 1800 (Drucker, 1985). According to Say, an entrepreneur shifts economic resources out of an area of lower and into an area of higher productivity and greater yield. Drucker says that they exhibit purposeful innovation as their principle tool, when making these resource shifts. Yet, in these definitions, as W. J. Baumol contends, this apex figure of the free enterprise society remains one of the most elusive characters in the cast (Kanbur, 1980)

Structural Differentiation, Technology, and Employee Fringe Benefits : A Model of Formal Organization

This study investigated the extent to which the structural differentiation and the technology of private industry organizations were related to employee fringe benefits in South Dakota. This was accomplished through the development and testing of a theoretical framework and model which represented the modification and synthesis of Max Weber\u27s theory of bureaucracy and Peter Blau\u27s theory of structural differentiation. Using a mailed questionnaire, data were obtained on measures of structural differentiation, technology, and employee fringe benefits from a sample of the population of all private industry organizations in South Dakota which had 10 or more employees. The measurement of unionization and environment were included in the modeled relationships to test the possibilities for future research. This study established empirical support for the theoretical framework and modeled relationships between structural differentiation, technology, and fringe benefits. More specifically, using univariate multiple linear regression analysis, structural differentiation and technology were found to explain about half of the variation in dependent fringe benefits. The additional factors of unionization and environment did not receive support in this study. Included in this study was the analysis of two subgroups of organizations that were different in employee composition. One subgroup was represented by organizations that were composed of salaried (professional) employees, with no hourly employees reported. The other subgroup exhibited the opposite employment characteristics. When compared, the salaried subgroup exhibited more structural differentiation and substantially explained more of the variation (61 percent) in fringe benefits than the hourly subgroup (23 percent). This finding suggested further support for the associations developed in the theoretical orientation, where increasing levels of bureaucratization, as measured by structural differentiation, were associated with increasing professionalization and fringe benefits

A Comparison of the Frequency and Effectiveness of Contemporary Preaching in the Lutheran Church—Missouri Synod and Protestantism on Selected Social Issues as Represented in the Concordia Pulpit and the Pulpit Digest

It is not the purpose of this paper to establish the ideal frequency for directly dealing with social issues from the pulpit. The purpose is rather to compare objectively the instances of preaching on social themes found in the Concordia Pulpit and the Pulpit Digest and to allow the reader to determine the ideal frequency for himself. It may be helpful, nevertheless, to present another\u27s opinion on the matter. One man may say it is never necessary to preach on social themes because, if the Gospel is preached, the Kingdom of God is established and the problems of society are thereby mended. Preachers through the years, however, have found it helpful, if not necessary9 to preach the Gospel to specific goals of sanctification, ie., to mundane problems which distress Christians. Once it has been granted that preaching on social issues is necessary, one must determine what percentage of the sermons which a congregation hears should be devoted to such a direct presentation and solution of social problems. In speaking of controversial issues, a scope somewhat narrower than social issues, Harold A. Bosley recommends the number which he preached during the two years of 1950 to 1952. Of approximately one hundred sermons, he lists thirteen which deal with controversial issues by the direct method or 13 per cent