Product design history

In summary, the final properties of thermoplastic articles depend both on the molecular structure of the polymer and on the details of the fabrication operations. This is a disadvantage, in one sense, since it makes product design more complicated than with other materials that are less history-dependent. On the other hand, this feature confers an important advantage on plastics because fabrication particulars are additional parameters that can be exploited to vary the costs or balance of properties of the products. 

This entry gives an introduction to the history of CAPE, general characteristics, and, structure. It describes in more detail the most significant and characteristic branch of CAPE— process synthesis, and introduces the most important new area of CAPE applications—product design. A few conclusions and... 

A traceability model extends a NATURE process model in order to enable the almost automatic capture of extended traceability information concerning the design history inside process-integrated tools. It is able to represent the process steps executed, the products involved, the major decisions taken, and their possible interrelations. 

The initial design and the commercial survival of a plasticizer are highly dependent upon imparting a desirable property to the finished product. The history of this technology is the story of progressive solutions of technical and commercial problems toward a goal of marketing excellent-quality products at the most reasonable price. 

Human factors audits can be applied, as can human factors itself, to both products and processes. Both applications have much in common, as any process can be considered as a product of a design procedure, but this chapter emphasizes process audits because product evaluation is covered in detail in Chapter 49. Product usability audits have their own history (e.g., Malde 1992), which is best accessed through the product design and evaluation literature (e.g., McQelland 1990). 

The shortcomings in these areas include incomplete and inconsistent medication history in patient charts, pharmaceutical care not provided routinely, large number of abbreviations used on preprinted forms and in medication communications (verbal and written), medication brands changed without the knowledge of surgical teams or technicians, hazardous chemical found in close proximity to products designated for patient use, top of anesthesia carts cluttered, medication "stashes" found in selected areas, inconsistent preoperative teaching of patients, and inconsistent system of double-checks [10]. 

The DHF is a compilation of records which describes the design history of a finished product. They have been highlighted in the previous points and include ... 

Is it possible to have a productive design without philosophy The answer is definitely no. It may seem at first instance that in engineering education social, economic, cnltnral and historical dimensions may provide such a situation, but after some test it becomes clear that without philosophy any of such non-numer-ical courses can achieve its goal. It is obvious that not sayings but core knowledge may have active role by philosophy only, otherwise such knowledge will remain as static in mind. One may think that the culture motivates, but history indicates that culture without philosophy cannot lead to productivity, however, remains local and comparatively are meager. 

Many molded and extruded products are prepared from GP plasticizers with DINP offering the best compromise between price and performance. Products designed for outdoor applications will often use more permanent plasticizers such as DIDP, DPHP, L9P, or L911P. Many medical devices still continue to use DEHP because of its very long history of safe use and product approvals. In the toy market, the industry has already moved to the use of nonphthal-ate plasticizers such as blends of citrates, TXIB, or dibenzoates with DEHTP or DINCH. 

The mechanical properties reported in the literature for molybdenum and its alloys are frequently at variance. That this should be so is not surprising as the properties of molybdenum and its alloys are greatly affected by the prior history of the material, both thermal and mechanical. Far too often values are used without reference to the sources of the material, various states of heat treatment, etc. When mechanical properties are an important feature of the design application, advice should always be sought on the suitability as only the manufacturer has the complete data on the history of his own product. Physical and some typical mechanical properties given for general guidance are shown in Tables 5.2 and 5.3. 

As an example, for room-temperature applications most metals can be considered to be truly elastic. When stresses beyond the yield point are permitted in the design, permanent deformation is considered to be a function only of applied load and can be determined directly from the stress-strain diagram. The behavior of most plastics is much more dependent on the time of application of the load, the past history of loading, the current and past temperature cycles, and the environmental conditions. Ignorance of these conditions has resulted in the appearance on the market of plastic products that were improperly designed. Fortunately, product performance has been greatly improved as the amount of technical information on the mechanical properties of plastics has increased in the past half century. More importantly, designers have become more familiar with the behavior of plastics rather than... 

For those not familiar with this type information recognize that the viscoelastic behavior of plastics shows that their deformations are dependent on such factors as the time under load and temperature conditions. Therefore, when structural (load bearing) plastic products are to be designed, it must be remembered that the standard equations that have been historically available for designing steel springs, beams, plates, cylinders, etc. have all been derived under the assumptions that (1) the strains are small, (2) the modulus is constant, (3) the strains are independent of the loading rate or history and are immediately reversible, (4) the material is isotropic, and (5) the material behaves in the same way in tension and compression. 

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