INSTITUTIONAL AFFILIATION OF AUTHORS IN THE AMERICAN JOURNAL OF AGRICULTURAL ECONOMICS, 1988-1992

Opaluch and Just reported the top 20 departments in pages per faculty of articles in the American Journal of Agricultural Economics for the five year period 1968-1972. To determine how much has changed and how much has not during the intervening two decades, the analysis was repeated for the five year period 1988-1992. Some things seem not to change. University of California, Berkeley, remains at the pinnacle twenty years later. And 13 of the top 20 departments two decades ago, remain there during the 1988-1992 period. But seven did change, and the most notable aspect is that the number of Northeast departments in the top 20 rose from two to five.Teaching/Communication/Extension/Profession,

Computational experience with a three-dimensional rotary engine combustion model

A new computer code was developed to analyze the chemically reactive flow and spray combustion processes occurring inside a stratified-charge rotary engine. Mathematical and numerical details of the new code were recently described by the present authors. The results are presented of limited, initial computational trials as a first step in a long-term assessment/validation process. The engine configuration studied was chosen to approximate existing rotary engine flow visualization and hot firing test rigs. Typical results include: (1) pressure and temperature histories, (2) torque generated by the nonuniform pressure distribution within the chamber, (3) energy release rates, and (4) various flow-related phenomena. These are discussed and compared with other predictions reported in the literature. The adequacy or need for improvement in the spray/combustion models and the need for incorporating an appropriate turbulence model are also discussed

Experimental study of noise reduction for an unstiffened cylindrical model of an airplane fuselage

Noise reduction measurements were made for a simplified model of an airplane fuselage consisting of an unstiffened aluminum cylinder 0.5 m in diameter by 1.2 m long with a 1.6-mm-thick wall. Noise reduction was first measured with a reverberant field pink-noise load on the cylinder exterior. Next, noise reduction was measured by using a propeller to provide a more realistic noise load on the cylinder. Structural resonance frequencies and acoustic reverberation times for the cylinder interior volume were also measured. Comparison of data from the relatively simple test using reverberant-field noise with data from the more complex propeller-noise tests indicates some similarity in both the overall noise reduction and the spectral distribution. However, all of the test parameters investigated (propeller speed, blade pitch, and tip clearance) had some effect on the noise-reduction spectra. Thus, the amount of noise reduction achieved appears to be somewhat dependent upon the spectral and spatial characteristics of the flight conditions. Information is also presented on cyclinder resonance frequencies, damping, and characteristics of propeller-noise loads

Analysis of rotary engine combustion processes based on unsteady, three-dimensional computations

A new computer code was developed for predicting the turbulent, and chemically reacting flows with sprays occurring inside of a stratified charge rotary engine. The solution procedure is based on an Eulerian Lagrangian approach where the unsteady, 3-D Navier-Stokes equations for a perfect gas mixture with variable properties are solved in generalized, Eulerian coordinates on a moving grid by making use of an implicit finite volume, Steger-Warming flux vector splitting scheme, and the liquid phase equations are solved in Lagrangian coordinates. Both the details of the numerical algorithm and the finite difference predictions of the combustor flow field during the opening of exhaust and/or intake, and also during fuel vaporization and combustion, are presented

Static inverters which sum a plurality of waves Patent

Describing static inverter with single or multiple phase outpu

A dc to dc converter

The object of the invention is to provide an improved converter for converting one direct current voltage to another. A plurality of phased square wave voltages are provided from a ring counter through amplifiers to a like plurality of output transformers. Each of these transformers has two windings, and S(1) winding and an S(2) winding. The S(1) windings are connected in series, then the S(2) windings are connected in series, and finally, the two sets of windings are connected in series. One of six SCRs is connected between each two series connected windings to a positive output terminal and one of diodes is connected between each set of two windings of a zero output terminal. By virtue of this configuration, a quite high average direct current voltage is obtained, which varies between full voltage and two-thirds full voltage rather than from full voltage to zero. Further, its variation, ripple frequency, is reduced to one-sixth of that present in a single phase system. Application to raising battery voltage for an ion propulsion system is mentioned

The role of the Initial Teacher Training Coordinator in the school based element of partnership: to what extent does the Co-ordinator undertake supervision of aspects of quality assurance?

Over the last 14 years, Universities and colleges have organised school placements and award qualifications whilst teachers, acting as mentors take the lead in guiding, supervising and assessing students on lengthy teaching placements. Partnership developed quickly in response to legislation and Sheffield Hallam University was among the first of the Universities to 'sign up' to the new partnership model in 1992. The Partnership Survey 2006 reported on in this paper has focussed on the Senior Liaison Tutor with a view to finding out their views on their role, and perceived contributions to the quality assurance of the partnership. The survey focussed on some of the key issues identified in previous studies and meetings of the Partnership Management Board.</p

The role of the initial teacher training co-ordinator: secondary headteachers' and ITT co-ordinators' perspectives

The roles of ITT co-ordinator (ITTC) and CPD co-ordinator have become well established in secondary schools in England. However there is usually a separation of responsibilities for these areas within schools. The introduction of a new Standards Framework and other government policies such as the remodelling of the workforce in schools (DfES, 2003, TDA, 2007a) provide schools with opportunity to revisit these roles. A consequence of remodelling has been a rapid expansion of support staff in schools to assist teachers and one aspect of this contractual change is that support staff are taking on administrative tasks, formerly done by teachers. A further aspect is that CPD Coordinators now have responsibility for staff development cross the wider workforce. During 2007, Schools have used remodelling as an opportunity to review their management structures throughout the school including the organisation of staff development and how the school is contributing to the training of new teachers. In this paper we consider how the role of the ITTC is changing using data from interviews with Head Teachers and ITTCs from a sample of secondary schools that are in partnership with Sheffield Hallam University. Data collection took place in April and May 2007.</p

P And S Wave Velocity Determination

There are three general methods that can be used to determine formation velocities from full waveform logs. The first approach is to make use of the data from the entire waveform. This type of velocity analysis is performed either in the frequency domain (i.e. f-k analysis or the two station method) or in the time domain (I.e. velocity spectral analysis). The second approach is to identify the P wave pulses on individual traces and to determine delay times between traces. In conventional acoustic logging this technique has been used successfully to determine the compressional wave velocities. The third approach' is to use the phase velocity of the gUided waves (Pseudo-Rayleigh) to determine the shear velocity. Each of these approaches have certain advantages and limitations depending on the tool characteristics (number of records, frequency response), formation properties (high or low shear velocity), and computation times required. The effect of these parameters upon each method of velocity determination is presented