Materials and Man's Needs Materials Science and Engineering -- Volume I, The History, Scope, and Nature of Materials Science and Engineering (1975) / Chapter Skim
Currently Skimming:
3. Materials Science and Engineering as a Multidiscipline
3. Materials Science and Engineering as a Multidiscipline
Pages 161-266
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 163... ...
The engineering materials are then fashioned by manufacturing processes into shapes and parts which are assembled to make a useful end-product. The product, once its useful life has finished, is eventually returned as waste to the earth, or it undergoes dismantling and material recovery to provide basic materials to feed into the materials cycle again.
|
From page 164... ...
Increasingly, therefore, it is necessary for the specialist in MSE to consider the effects of technological changes on the complete system of the total materials cycle, including energy consumption and environmental quality. INNOVATION IN MATERIALS SCIENCE AND ENGINEERING MSE has become a basic instrument in bringing about technological changes.
|
From page 165... ...
New materials made from more abundant raw materials can often be developed as substitutes for old ones made from scarcer or ecologically less desirable raw materials; new ways can often be found for performing needed technological functions, e.g transistors have replaced vacuum-tube triodes as basic amplifying elements in electronic circuits, and in more recent years integrated circuits replaced boxes of complex electronic equipment made up of many components. Looking ahead with another example, present work in certain forms of levitated ground transport, if successful, could lead to greatly increased demands for new magnetic or superconducting alloys.
|
From page 166... ...
For that reason, he was materialsource oriented and tended to be more affiliated with the material supplier than with the material consumer. In recent decades, the interest in materials properties has been broadened from that of the supplier to include that of the consumer.
|
From page 167... ...
In the solid~state electronics industry, we find an example where highly sophisticated and costly effort on materials is justified in terms of the overall product value -- both the processing of semiconductor material and the assembly into discrete devices or integrated circuits requires a degree of control which would be unbelievable in most industrial situations. The term experience~based technology, or low technology, is used to refer to programs which are not science intensive -- in other words, which rely on more empirical approaches or which may be highly forgiving of manufacturing and processing variations, Typically, large material quantities are involved so that unit material costs are important.
|
From page 168... ...
S has been in the forefront, such as aerospace, computers, and nuclear reactors, have also been generally associated with international trade surpluses for the U
|
From page 169... ...
In the past the physicist has too often made unrealistic assumptions about the composition, purity, and quality of the materials of his researches; the metallurgist has too often not understood sufficiently how the physical phenomena exhibited by a solid relate to its structure and composition. We believe that materials research provides a natural meeting-ground for specialists from the various scientific and engineering disciplines, from basic research to applied research, development and engineering, and that the pressure for such interdisciplinary collaboration will grow in the future.
|
From page 170... ...
Second, there is growing awareness of the integral role played by materials in the general fabric of society and of the increasingly sophisticated demands made on materials by complex technologies. Third, this increasing recognition of the importance of materials is coupled with a growing appreciation of the ways in which the societal demands for materials often have an adverse effect on environmental quality.
|
From page 171... ...
MSE also interacts strongly with related activities: education and teaching, commerce and industrial economics, national security, and environmental quality. The multidisciplinary nature of the field undoubtedly aids its involvement in a wide range of human concerns and interests.
|
From page 172... ...
Either directly or through the intermediary of these technologies, the field is also very relevant to several other key concerns of mankind, particularly environmental quality and the conservation of natural material and energy resources' In sum, the field plays an essential role in raising mankind~s standard of living and in enhancing economic, social, and national security. MSE is, then, a necessary' though by no means sufficient, compQnent for the progress and even survival of mankind.
|
From page 173... ...
3-11 zl c <¢ H o UP lo, ~0 .
|
From page 174... ...
3-12 CO Z o H En ¢ H Pa O CO Cal U: o PA o ¢ En lo. earl o Cal _ .
|
From page 175... ...
of OH |
From page 177... ...
Razor Blades (See Appendix 3C; p.
|
From page 178... ...
As in the case of the transistor, the early effort was on basic understanding, but there was also a perceived need to improve on natural fibers. In time, engineering emphasis was added but not at the expense of further scientific investigation so that we now find the general problem of synthetic fibers being attacked across the entire spectrum from basic science to engineering.
|
From page 179... ...
In the rapid development of integrated circuits, effective coupling has been achieved principally through cross-licensing of patents, among industrial organizations which are highly competitive. Whereas the transistor required important new scientific understanding, the creation of the sophisticated integrated circuits resulted principally from inventiveness and engineering ingenuity, particularly in processing technology.
|
From page 180... ...
Scientific studies in support of laser host materials led to the discovery of a commercially significant red phosphor. A central element of this program was the ability of the investigators to pursue and exploit unpredicted observations.
|
From page 181... ...
An alloy was chosen on the basis of its high modulus, but its strength suffered from the welding process. A better and stronger overall product could have been obtained by the choice of a stainless steel with less strength but superior welding characteristics.
|
From page 182... ...
it is science in action to meet man's needs even though, at any given time, a number of the activities in the field will be more curiositymotivated than application-oriented. This multidisciplinary field embraces activities in the traditional single disciplines, including the work of individuals, as well as interdisciplinary activities which, by definition, require the collaboration of two or more individuals.
|
From page 183... ...
Nature of Materials Research Our definition of MSE includes both the generation and the application of knowledge about materials. Materials science is usually concerned with the generation part' materials engineering with the application part.
|
From page 184... ...
In addition to the above operational forces which are serving to shape the role of materials research, there are also significant internal, intellectual forces. It is now recognized that interests in basic phenomena and
|
From page 186... ...
and the material types are many, but increasingly those engaged in materials research are acquiring the ability to maneuver in these many dimensions in whatever way seems most effective for achieving the desired scientific or technological goal. Nature of Materials Development, Design, and Engineering Society wants things or services which require materials, but there must be the inte~-luediary of a design or application specialist to transform material into a product or service, Design is used here in the broadest sense of "the process of selecting the means and contriving the elements, steps, and procedures for producing what will adequately satisfy some need,''2 or in an engineering context, "the drawing up of specifications as to structure, forms, positions, materials, texture, accessories, decorations in the form of a layout for setting up, building, or fabrication.
|
From page 187... ...
These products are composed of systems of materials, each chosen to fit a particular profile of functional properties and environmental requirements. Modern technological products -nuclear reactors jet engines, integrated circuits, etc.
|
From page 188... ...
One of the most important emerging forces in the materials cycle is the limited availability of certain raw materials. These growing shortages on various time-scales have important repercussions throughout the cycle, but particularly spotlight a vital role for MSE -- to develop substitute materials made from abundant or renewable natural resources and to engineer ways of making do with considerably less of the scarce materials.
|
From page 189... ...
3~27 -- - ~ ~ a. DEF'~lriou or runcT'o" ~ Ho _ ~ .
|
From page 190... ...
In summary, there will be growing need in the future to pursue the systems approach both internally and externally in major MSE programs The complexity of modern technological hardware requires the systems approach on internal materials systems; the mounting problems of resource availability, fuel supplies, and environmental quality require the systems approach to be applied to MSE engineering in an external context as well. Multidisciplinary and Interdisciplinary Activities We have already noted that the field of MSE is multidisciplinary in that it embraces activities in a wide range of the traditional disciplinary areas, activities which are very often undertaken by individuals.
|
From page 191... ...
COUPLING WITHIN THE FIELD OF MATERIALS SCIENCE AND ENGINEERING As noted, the technological needs of society are generally not congruent with the traditional scientific and engineering disciplines. Nor can they usually be met by engineering alone, but require a balanced range of activities extending from basic research to marketing.
|
From page 192... ...
Loosely-Coupled Multidisciplinary Activities, Tightly-Coupled Interdisciplinary Activities MSE is a multidisciplinary (MD) field within which there are increasing opportunities for interdisciplinary (ID)
|
From page 193... ...
The more tightly-coupled ID mode of collaboration may involve a group of professionals, drawn together from various disciplines to tackle a specific mission or reach a stated goal. It implies a commitment on the part of the individual to choose his own direction and the corresponding time scale in support of the ID group objective, The freedom of the individual has to take second place to the overriding importance of reaching the group's overall objective on time' The individual is constrained to spend a major part, if not all, of his time working on the group project.
|
From page 194... ...
One of the most important of these is the recognition of the defect nature of solids. At one time it was thought that single crystals were nearly perfect geometric arrays of atoms or molecules in the particular structure revealed by tray diffraction.
|
From page 195... ...
Importance of Purpose A hallmark of a continuingly successful R & D organization is a clear recognition by all concerned of the overall long-term purpose, mission, or theme of the organization. Success of inhouse governmental laboratories and industrial laboratories in MSE has reflected especially the degree to which the overall mission of the laboratory 'has been defined, understood, and accepted, so as to provide a central interest that draws professionals from different disciplines together and provides continuity in basic studies beyond the span of individual development projects.
|
From page 196... ...
___ sees no reason why the selection of appropriate themes for foster effective interdisciplinary activities should compromise the traditional academic standards of quality and freedom. Interdisciplinary research need not be of inferior quality to the traditional research by an individual -often the converse will be true.
|
From page 197... ...
Size of Organization Small organizations, industrial or governmental, may be able to support only small programs in MSE if the usual commercial factors are operating. These small programs then have to be very directly related to the productobjectives of the organization if they are to be regarded as cost-effective -the outcome of, and time scales involved in, more basic research programs are generally too uncertain.
|
From page 198... ...
A corollary to this discussion is that, generally, small organizations are not justified to engage in basic materials research but have to concentrate on development, engineering, and marketing -- entrepreneurship. However, to do this still requires individuals who are able to interpret and exploit the results of basic research performed elsewhere.
|
From page 199... ...
If a given program is large, requiring several individuals in the materials and applications groups, or if the problem is of such a nature as to require a wide spectrum of disciplines, then the key individual or champion must have an unusually wide span of interests and knowledge. Thus, at least one individual in the group must have an intimate understanding of the overall program and how the various elements will combine for the ultimate solution.
|
From page 200... ...
Materials R & D is normally carried out in a group approach, too. It is often associated with development programs whose magnitude and time scales require a number of individuals to complete the job within the allocated time.
|
From page 201... ...
Although the documentation and publication record is good in materials R & D, there is no way to transmit on paper the many subtleties and sensitivities connected with the processes for producing new materials with special properties. Experience has repeatedly shown that a complex new materials process developed at one site can more easily be transferred to a different manufacturing location if some of the key individuals are also transferred.
|
From page 202... ...
Roadblocks to Effective Coupling Many of the obstacles to effective coupling can be inferred from the preceding sections but a few additional comments are in order. In the early stages of an interdisciplinary materials program, the group may be composed mainly of basic research scientists with a relatively small number of engineers.
|
From page 203... ...
During the past dozen years, academia has been remarkably effective in preparing individuals for careers in materials science by training at the masters, doctoral, and postdoctoral levels. The establishment and support of the interdisciplinary materials research laboratories played a central role in this response of the universities to emerging needs of technology.
|
From page 204... ...
3-42 U) erl o A furl er1 Cal En o U)
|
From page 206... ...
However, materials research in the interdisciplinary mode has not faired quite so well when compared with the better industrial and governmental laboratories. The universities have two cardinal principles which interfere with interdisciplinary materials research on campus.
|
From page 207... ...
Materials research is generally interdisciplinary in nature when conducted in industrial or governmental laboratories. Materials research laboratories on the campus, therefore, are ideally situated for bridging between the traditional discipline-oriented activities of universities and the interdisciplinary activities outside the campus.
|
From page 208... ...
Funding and Reward Mechanisms In the traditional academic departments, it is usual for individual faculty members to seek their own research grants and contracts. Such practice is less useful in interdisciplinary research projects which are more subject to changing external requirements.
|
From page 209... ...
Moreover, the new high-pressure techniques also became available to the entire technical community. As a result, there was a sudden increase in studies on the effect of high pressure on material properties and on the synthesis of new materials at high temperature and pressure.
|
From page 210... ...
In some instances, we find individual companies or sectors of the economy where a challenging new goal has been internally generated, and where these internal goals have been sufficiently demanding to require a science-intensive approach for their solution. Some examples are the development of polymer~coated razor blades, the creation of the synthetic fiber industry, and the integrated-circuit business.
|
From page 211... ...
Thus, all indicators seem to point to increasing emphasis on materials development which makes maximum usage of scientific understanding closely integrated with design and application in the broad sense, and which is fully balanced with regard to the overall materials cycle. Changing Industrial Scene for Materials Science and Engineering Many of the outstanding advances in MSE have been achieved by industrial organizations making it a practice to support comprehensive, suitably balanced, and coupled R & D programs.
|
From page 212... ...
Enough basis is presented elsewhere in this report to indicate the many fresh technical challenges facing industry in addition to those which arise directly from the growing problems of materials availability and concern over environmental quality. Many of the newer challenges can be met only with the help of a sustained, science-intensive approach; reliance cannot be placed solely on the experience-intensive approach, inasmuch as often there is no such experience.
|
From page 213... ...
More recently, emphasis has shifted toward goals which more directly affect the daily lives of the general population such as energy, health care, transportation, environmental quality, housing and urban renewal. Dramatic progress in meeting these goals can only be achieved through considerable innovation, and much of that innovation will be in materials technology.
|
From page 214... ...
These three agencies have accounted for some 90% of support for R & D in (metallurgy and) materials engineering in FY 66 and 81% in FY 717 (See Table 3.3~.
|
From page 215... ...
3-53 Girl six a' .
|
From page 216... ...
3-54 Girl o _' .
|
From page 217... ...
As time goes on, however, needs will become evident for further materials development and refinement. Indeed, we already see examples in the area of environmental quality and pollution.
|
From page 218... ...
When viewed in today's perspective, the materials community might be criticized for giving inadequate attention to certain elements of the materials cycle such as pollution and recycling, but every evidence indicates that MSE will respond as new goals are defined and requirements spelled out. In the following chapter, the relations between MSE and several newly evolved national goals is described in sufficient detail to portray the kinds of contributions which MSE can be expected to make.
|
From page 219... ...
Recent development of new materials accomplished by close cooperation between materials specialists and medical practitioners has dramatized the progress which can be made in this field. Such instances afford excellent illustrations of the interdisciplinary nature of this activity, the need for additional scientific understanding, and the opportunities for new modes of interaction between the materials community and medical science.
|
From page 220... ...
For this purpose, various mechanical and electronic devices are employed to measure deflections and loads, or to monitor vibrations, in order to determine the modulus of elasticity. From such testing, other strength properties such as modulus of rupture are estimated through correlative procedures.
|
From page 221... ...
However, it will also be necessary to determine the relationships between these parameters and specific discontinuities as they further relate to strength properties. Fundamental studies in this field involve fracture mechanics, stress-wave theory, mathematical modelling, physics, and basic wood structure.
|
From page 222... ...
For a fixed reentry velocity and angle, an increase in ballistic coefficient produces higher heating rates and increased total integrated heat. The value of maximum deceleration is not strongly dependent on ballistic coefficient, but rather depends on reentry velocity and angle, with increases in velocity and angle yielding ah increase in deceleration loads.
|
From page 223... ...
Therefore, the manned lunar mission, entry corridor, convective heating and deceleration limits defined the major design requirements for reentry of the Apollo command module. By the mid 1960's, studies had shown that the previously used burn-up philosophy during reentry of SNAP devices was unsafe in that a potential existed for dispersing radioactive material in the earth's atmosphere.
|
From page 225... ...
Phenolic nylon tiles over a supporting honeycombsandwich structure of stainless steel was the approach finally selected. The main design requirements for the ablator were that it limit the temperature at the ablator-steel interface to 600° F during entry, that it be compatible with the steel substructure,and that it survive thermal cycling from -250° F to +250° F prior to entry.
|
From page 226... ...
Supporting Materials Program It is evident from the previous description of the reentry environment and heatshield design problems that synthesis of materials tailored to meet the design requirements was essential. This role was fulfilled by MSE.
|
From page 227... ...
In the manner just described, also addressed in the MSE mode are: fiber technology, char technology, layup technology, ablation-reaction chemistry, adhesion, physics of transpiration cooling, all to optimize each desired attribute. Then parametric studies are used to distill the mixture of best attributes into one best ablator for a given application.
|
From page 228... ...
The importance of MSE in the heatshield design area is further exemplified when one considers the serious problem of variability of material properties in materials supplied by commercial vendors. Vehicle design
|
From page 229... ...
APPENDIX 3B Discovery of the Transistor One of the best-known examples of multidisciplinary and interdisciplinary R & D is that which led to the discovery of the transistor and the subsequent creation of a whole new technology. The transistor was discovered in the Bell Telephone Laboratories.
|
From page 230... ...
Shockley and Fisk concluded that the most promising and relevant area in which one might look for new electronic phenomena for amplification lay in semiconductors -- if one could understand the basic physical and material science. The best theory in those early days did not explain the relation between structure and function in any quantitative way for copper oxide or germanium rectifiers.
|
From page 231... ...
They had no concrete ideas on what form any new electronic device might take, but they had faith that basic understanding of semiconductors could lead to the snythesis of a new electronic device. Nobody could put a quantitative value on the probability of success or on how long it would take to succeed.
|
From page 232... ...
Based on this art, nevertheless, many important semiconductor devices were produced, notably for microwave detectors in radar. When the War ended, following Kelly's urging outlined earlier' researchers at Bell Laboratories resumed the attack on semiconductors.
|
From page 233... ...
From this point on, it is perhaps fair to say that, though physicists and electrical engineers continued to have many of the device ideas, the pace of progress in semiconductor R & D was determined very much by the progress of the chemists and metallurgists. Absolutely vital steps were the discovery of zone refining by Pfann and the development of ways to grow high-quality single crystals of germanium and silicon.
|
From page 234... ...
Fundamental studies of razor-blade edge geometry and metallurgy were undertaken using electron microscopy which was a new tool at that time. After considerable difficulty, techniques were devised to study razor blade edges with the electron microscope.
|
From page 235... ...
The PTFE coatings were removed from the blade edge after shaving by dissolving the steel and floating off the coating, which could be shown to remain intact across the ultimate edge in many places. More recent work on razor blades, where electron microscopy and physical metallurgy have played a predominant role, has been the development of edgestrengthening metallic alloy coatings.
|
From page 236... ...
The Crept alloy exhibits a DPHN hardness in excess of 1400. This is far in excess of the normal hardness of PTFE-coated razor blades which range in hardness from 550 to 650 DPHNe X-ray diffraction techniques have made it possible to characterize the structure of the Cr3Pt alloy in bulk, while the electron microscope has made that possible in then films useful for razor blade edges.
|
From page 237... ...
These consisted principally of organic and physical chemists, the former to synthesize polymers and the latter to determine their properties. The role of the research chemists and their discoveries cannot be overemphasized in discussing the origins of synthetic fibers.
|
From page 238... ...
However, much had to be learned in the basic physical sciences before the structural aspects of materials which contribute to strength properties could be explained and exploited for producing synthetic f ibers .
|
From page 239... ...
The lowered molecular weight of the regenerated cellulose fibers rendered them weaker than silk fibers which possessed their high natural molecular weight, so that the high strength problem for synthetic fibers had not been solved. Thus, a large body of knowledge had been amassed and engineering aspects on the spinning and the packaging of rayon for market had been worked out by the time Carothers' group became productive in the preparation of new synthetic polymers.
|
From page 240... ...
As indicated above, highmolecular weight "superpolymers" were required in order to obtain fibers with tensile strengths comparable to that obtained from silk. During the early days of research on the polyesters and polyamides, another materials science played an important role in the development of synthetic fibers.
|
From page 241... ...
APPENDIX BE Textured Materials Textured polycrystalline materials, with physical properties related to those of single crystals, are finding an increasing number of applications in devices where strong mechanical, magnetic, and other physical properties are desired. The feature that distinguishes textured materials from others is the preferential directional alignment of the individual crystalline grains making up the material.
|
From page 242... ...
Within the Bell System, such control has led to improved soft magnetic alloys in wire and tape form for use in certain magnetic memory devices, and also to alloys with enhanced mechanical properties for springs and electrical connectors. In the latter, after final heat treatment, yield strengths of such materials as phosphor bronze, nickel silver, cupronickel, and copper beryllium have been, on the average, almost doubled without loss of ductility Elsewhere?
|
From page 243... ...
APPENDIX 3F Integrated Circuits The development of the transistor led to a number of basic techniques required for integrated circuits, such as semiconductor purification, crystal growth, alloying, diffusion, oxide masking? and epitaxial growth.
|
From page 244... ...
Some of the more important of these advances were made in the continuing effort to improve discrete transistors as mentioned earlier; however, their application to integrated circuits was rapidly recognized and exploited. The key developments were the application of photoresist and oxide etches to determine the regions into which impurities were to be diffused; the planar process using the above techniques for diffusion but leaving the silicon oxide layer on the surface to protect the ambient sensitive pen junctions; the use of evaporated and photoresist-patterned metal films on the oxide to interconnect the devices; and the application of chemical vapor deposition for growing thin epitaxial layers of silicon on silicon substrates containing different impurity doping.
|
From page 245... ...
By starting with a heavily doped, hence low resistivity, silicon slice of sufficient thickness to provide the necessary mechanical strength, and growing a lightly doped epitaxial layer only thick enough to contain the active regions of the transistor' a significant reduction was obtained in collector series resistance. This same technique was subsequently applied to silicon integrated circuits to achieve electrical isolation between components.
|
From page 246... ...
The high electronic field present across the oxide during operation of the device causes the sodium to migrate, and transistor characteristics shift accordingly. Many man-years of effort in several laboratories by chemists, physicists, and electrical engineers were required before the causes of, and cures for, these instabilities reached a point where reliable MOS integrated circuits became practical.
|
From page 247... ...
~ Planar Integrated Circuits windows 200-500 Am m100 components ~First Integrated Circuit (1958) Phase shift oscillator m20 components Kilby-E.E.-Texas , Instruments .
|
From page 248... ...
Most grew out of applied research and engineering, with the latter predominating. The development of integrated circuits, in fact the entire development of modern electronic devices, was not only a case where the MSE approach was followed' but one where this approach was essential for success to be achieved so effectively.
|
From page 249... ...
To meet current cable transmission requirements and provide equivalent copper conductivity, the electrical conductivity of aluminum was specified as 60 percent copper standard and a 2-gage size larger cross~section was used. (The cable size penalty incurred in adopting aluminum alloys with less than 60 percent arises not only from larger conductor cross~sections but also from thicker insulation needed to maintain cable capacitance requirements.)
|
From page 250... ...
and emphasized critical path considerations and the desirability of a systems approach. Having solved the basic problems in an all-aluminum conductor system, the expedient nature of a copper-clad aluminum substitution becomes more apparent' APPENDIX 3H Polymer Latex-Modified Portland Cement A '"polymer latex-modified Portland cement" is obtained when a part of *
|
From page 251... ...
Grenley, a polymer chemist at the Dow Chemical Company' experienced in polymer latex synthesis. Jerry Isenburg, a physicist at the Dow Chemical Company, specializing in Portland cement rheology and scanning electron microscopy.
|
From page 252... ...
In any case, the "cement gel" that is progressively developed as the product of these hydration reactions comprises chemical species of high specific surface. The new surface area that can ultimately develop may be 500 to 1000 times larger than that of the initial cement grains, and the strength properties of the hardened cement are importantly linked to this increased surface area, and to the structure and packing density of the colloidal hydration products.
|
From page 253... ...
A team of workers at the Philips Laboratory independently discovered the potential for color TV applications of europium-doped yttrium oxide phosphors and the related material, gadolinium oxides Others had independently explored oxy-sulf~de systems and had developed the yttrium compound Y2O2S:Eu. The following is a description of the development work of three individuals at the General Telephone and Electronic Laboratory in Palo Alto, which led to the development of the new red phosphor of commercial importance.
|
From page 254... ...
The blue and green phosphors were operated at reduced electron current to balance with the red phosphor which exhibited current saturation and a color short of bright red. In 1961, an interdisciplinary team at General Telephone and Electronics developed a new red phosphor material with a redder color and a capability of operation at higher energies.
|
From page 255... ...
techniques for the production of single crystals of refractory oxides through growth of refractory oxides for his studies on ferromagnets. The standard Verneuil apparatus is a concentric-tube oxy-hydrogen burner in which the center tube is used to supply the raw material for crystal growth and oxygen.
|
From page 256... ...
Crystalline field splitting is the term used to describe variation in energy level due to the interaction between the electric fields in the crystal and a specific electron state or orbit. If the electron state is not spherically symmetrical and if the crystalline field varies along major directions of the lattice 9 the energy level will depend on the relative orientation between the electron orbit and the crystal.
|
From page 257... ...
With respect to the phosphor development, most of the close interaction required had already been accomplished in the garnet work. Yttrium oxide was chosen as a laser-host candidate for several reasons.
|
From page 258... ...
Results Lefever was able to grow yttrium-oxide single crystals with europium doping. In order to do so, he had to develop a modification of the flame fusion burner, and then in order to prevent cracking of the crystals he devised a technique for protecting the growing crystal with a coating of powder which reduced thermal gradients in the crystal.
|
From page 259... ...
The principal application is as envelopes for high intensity, sodium vapor lamps. Related development of useful products has been extended to ceramics whose major components are yttrium oxide (G.E.'s Yttralox for infrared-transmitting windows)
|
From page 260... ...
2. Disciplinary Differences May Produce a Power Hierarchy, Inhibiting the Conduct of Effective Interdisciplinary Research: When interdisciplinary research takes place within complex research organizations' participants are unlikely to have equal formal or informal status, which would produce strains in the relationships ...
|
From page 261... ...
Difficulties due to disciplinary orthodoxy appear to be most severe in academia as brought out clearly by the following discussion related to interdisciplinary research on environmental quality:* It will not be easy to begin new problem-focused programs at universities, despite the need for trained professionals and the seriousness of the problems, Dr.
|
From page 262... ...
The political interest in the environment demands proposals for action -on all time scales, from the immediate assault on pollution problems and other festering sores of today, to the long-term reconstruction of society in a better relation with environment. At present we are not equipped to make such proposals.
|
From page 263... ...
3-101 There appear to be certain characteristics of close collaboration: A From the standpoint of the research problem B
|
From page 264... ...
d) Interdisciplinary team research can be expensive.
|
From page 265... ...
Interdisciplinary research facilitates the creation of situations that may result in new and productive combinations. An interdisciplinary approach is valuable in contributing specific techniques and skills from various disciplines to each other.
|
From page 266... ...
3-104 k) Interdisciplinary research can be a valuable learning experience that can be utilized effectively for training purposes Many of the pitfalls and problems of interdisciplinary team research can be minimized or avoided by recognizing them in advance and guarding against them.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.