32,780 research outputs found
Holistic, Ethical Leadership for the 21st Century
The New Oxford American Dictionary (2001) delineates two definitions for a leader: “1) The person who leads or commands a group, organization, or country; a person followed by others. 2) A short strip of nonfunctioning material at each end of a reel of film or recording tape for connection to the spool.” How often does the latter definition seem more applicable for many of our educational leaders than the former? What are the philosophical foundations of leadership? What does a modern, ethical leader look like? These are just a few questions that will be explored in this article. The challenge beset for the educational leaders of the present and the future is one that will require a bridging and blending of old and new paradigms. A mere paradigm shift may not be sufficient–the term shift is still too mechanistic and linear to adequately describe this new approach. Rather, the modern ethical leader must create a paradigm blend. In the circular way of knowing, akin to the epistemology of the Lakota Sioux (Stolzman, 1986), this article will explore four aspects of modern educational leadership. First, the criticisms and attacks on the educational system will be addressed. Second, the aim of education will be analyzed through three lenses: axiology, epistemology, and ontology. Third, systemic education will be discussed. Fourth, the role of the modern/future educational leader will be explored: specifically regarding the need for him/her to address the concerns of the critics and bridge the divide between two paradigms of education. This essay is a brief exploration that delves into the shortcomings of the modern educational system, the core purposes of education, systemic educational paradigms, and the role of the 21st century ethical leader. The author’s goal is not to provide answers, nor propose a prescription for ethical leadership. Rather, the intent is to aid in focusing the direction which leaders must follow in order to be effective in this millennium. Similar to the manner in which Descartes shared his method of inquiry, the author will share part of his experience in learning and growing as an educational leader. “Thus my purpose here is not to teach the method that everyone should follow in order to conduct his reason correctly, but merely to show how I have tried to conduct mine” (Descartes, 1637/1980, p. 2)
Precise doping of metals by small gas flows
Simple method was developed for doping refractory metals with oxygen. The metal specimens are heated in a dynamic high-vacuum system. The system can be used for other oxygen absorption processes /such as low-pressure oxidation measurements/ and for gases other than oxygen
On the application of electric propulsion to satellite orbit adjustment and station keeping
Electric propulsion application to synchronous satellite orbit adjustment, stationkeeping, and attitude contro
Nickel base coating alloy
Zirconium is added to a Ni-30 Al (beta) intermetallic alloy in the range of 0.05 w/o to 0.25 w/o. This addition is made during melting or by using metal powders. The addition of zirconium improves the cyclic oxidation resistance of the alloys at temperatures above 1100 C
Asymptotics of Relativistic Spin Networks
The stationary phase technique is used to calculate asymptotic formulae for
SO(4) Relativistic Spin Networks. For the tetrahedral spin network this gives
the square of the Ponzano-Regge asymptotic formula for the SU(2) 6j symbol. For
the 4-simplex (10j-symbol) the asymptotic formula is compared with numerical
calculations of the Spin Network evaluation. Finally we discuss the asymptotics
of the SO(3,1) 10j-symbol.Comment: 31 pages, latex. v3: minor clarification
The 100,000-hour cyclic oxidation behavior at 815C (1500 F) of 33 high-temperature alloys
Commercial high-temperature Fe-, Ni-, and Co-base alloys were oxidized in air at 815 deg C for ten 1000-hour cycles. Specific weight change versus time curves were derived and the 10,000-hour surface oxides were analyzed by X-ray diffraction. The alloys were ranked by a combination of appearance and metal loss estimates derived from gravimetric data
A multiple linear regression analysis of hot corrosion attack on a series of nickel base turbine alloys
Multiple linear regression analysis was used to determine an equation for estimating hot corrosion attack for a series of Ni base cast turbine alloys. The U transform (i.e., 1/sin (% A/100) to the 1/2) was shown to give the best estimate of the dependent variable, y. A complete second degree equation is described for the centered" weight chemistries for the elements Cr, Al, Ti, Mo, W, Cb, Ta, and Co. In addition linear terms for the minor elements C, B, and Zr were added for a basic 47 term equation. The best reduced equation was determined by the stepwise selection method with essentially 13 terms. The Cr term was found to be the most important accounting for 60 percent of the explained variability hot corrosion attack
The effect of variations of cobalt content on the cyclic oxidation resistance of selected Ni-base superalloys
Cobalt levels were systematically varied in the Ni-base turbine alloys U-700 (cast), U-700m(PM/HIP), Waspaloy, Mar-M-247, In-738, Nimonic-115, U-720, and SX-R-150. The cobalt levels ranged from 0 wt % to the nominal commercial content in each alloy. The alloys were tested in cyclic oxidation in static air at 1000, 1100 and 1150 C for 500, 200 and 100 hr respectively. An oxidation attack parameter, Ka derived from the specific weight change versus time data was used to evaluate the oxidation behavior of the alloys along with X-ray diffraction analysis of the surface oxides. The alloys tend to form either Cr2O3/chromite spinel or Al2O3/aluminate spinel depending on the CR/Al ratio in the alloys. Alloys with a ratio of 3.5 or higher tend to favor the Cr oxides while those under 3.0 form mostly Al oxides. In general the Al2O3/aluminate spinel forming alloys have the better oxidation resistance. Increased cobalt content lowers the scaling resistance of the higher Cr alloys while a 5.0 wt % Co content is optimum for the Al controlling alloys. The refractory metals, particularly Ta, appear beneficial to both types of oxides perhaps due to the formation of the omni-present trirutile Ni(Ta,Cb,Mo,W)2O6. Both scales break down as increasing amounts of NiO is formed
The effect of 0.1 atomic percent zirconium on the cyclic oxidation behavior of beta-NiAl for 300 hours at 1200 C
The long time effect of 0.1 at percent Zr (0.2 wt percent Zr) on the cyclic oxidation behavior of hipped beta-NiAl was studied. Oxidation testing was performed in static air at 1200 C for up to 3000 one-hour exposure cycles. Specific weight change versus time data was modeled with the COSP computer program to analyze cyclic oxidation behavior. The Zr-free stoichiometric alloy oxidized and spalled randomly to bare metal between cycles at a rate high enough to deplete Al to a low enough level that oxidation breakaway took place as nonprotective NiO replaced the alpha-Al2O3/NiAl2O4 scale as the controlling oxide. The Zr minimized this severe type of spalling maintaining the protective alpha-Al2O3 scale even out to 3000 hours for the stoichiometric alloy with no significant Al depletion. A third beta-NiAl alloy containing 0.1 at percent Zr but with 10 percent less Al than the stoichiometric alloy was also tested and showed some depletion of Al, but the protective Al2O3/NiAl2O4 was still maintained to close to 2700 hours
The effects of Cr, Co, Al, Mo and Ta on the cyclic oxidation behavior of a prototype cast Ni-base superalloy based on a 2(5) composite statistically designed experiment
A series of cast Ni-base superalloys were systematically varied at selected levels of Co, Cr, Mo, Ta, and Al. The elemental levels varied were Mo, 0 to 4 percent; Cr, 6 to 18 percent; Co, 0 to 20 percent, Ta, 0 to 8 percent; and Al, 3.25 to 6.25 percent. The cyclic oxidation resistance was determined from specific weight change data as a function of time for 1 hr cycles in static air at 1100 C. The significant terms in decreasing order of their importance were Al, Ta, Cr2, Al-Cr, Cr-Co, Co2, Al-Mo, Cr-Mo, Al-Al, and Mo-Ta. The Al term alone accounted for close to 82 percent of the explained variability. The estimating equation showed that the Al level was the most important and should be at its 6.25 wt % maximum value. The Mo and Ta levels should also be at their maximum 4 and 8 wt % respectively. The cobalt composition should be as low as possible, i.e., 0 wt%. The Cr level optimum varies depending on the other 4 levels. The X-ray diffaction results indicate the most protective scales are alumina/aluminate spinel stabilizized with a tri-rutile oxide high in Ta and Mo
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