halil_kayhan_030070090_5th_week_words_part2

1. Solid Freeform Fabrication: (previous)

Any method of manufacturing solid mechanical parts without part-specific tooling or human intervention. The version called layered manufacturing is based on additive processes that build parts in layers. Rapid prototyping (RP) emphasizes speed and the initial applications of the technology, while the newer rapid prototyping and manufacturing (RP&M) stresses applications that results in functional parts, rather than models.

Solid freeform fabrication technologies use a computer graphic representation and simple stock material (powder, liquid, gas, sheets, and so on) to fabricate complex parts. Photopolymer systems build shapes using light to selectively solidify liquid photocurable resins. A number of other systems prefer powders as their stock material. Some examples of powder-based techniques are selective laser sintering [Fig. 3], 3-D printing, and 3-D laser cladding. Lamination systems operate with a variety of feedstock from paper sheets to metal plates. SFF deposition techniques include extrusion, ink-jets, 3-D welding, gas, and plasma spray [Table 11].

(Crawford, R.H.; Beaman, J.J.; “Solid Freeform Fabrication”, Spectrum, IEEE, Volume 36, Issue 2, page 36)

Solid Freeform Fabrication: (new) (Manufacturing method)

Solid freefom fabrication (SFF) is the name given to a class of manufacturing methods which allows the fabrication of three dimensional structures directly from computer aided design(CAD) data. SFF processes are genearally additive, in that material is selectivelly deposited to construct the part, rather than removed from a block or billet. Most SFF processes are also layered, meaning that a geometrical description of the part to be produced is cut by a set of parallel surfaces (planar or curved) and the intersections of the part and each surface - referred to as slices or layers- are fabricated sequeentially. Together, these two properties mean that SFF processes are subject to very different constraints than traditional material removal-based manufacturing. Nearly arbitrary part geometries are achievable, no tooling is required, mating parts and fully assembled mechanisms can be combined, allowing functionally graded material properties.

(Jordan Pollack, Mark Bedau, Phil Husbands, Takashi Ikegami and Richard A. Watson,               Artificial Life IX, page 100)

2. Motion Analysis:

Motion analysis is a central problem in computer vision, and the past two decades have seen improtant advances in this field. However, visual motion is still often considered on a pixel-by-pixel basis, even though this ignores the fact that image regions corresponding to a single object usually undergo motion that is highly correlated.Further, it is often to interest to accurately measure the boundaries of moving regions.In the case of articulated motion, especially human motion, discovering motion boundaries is non-trivial but an important task nonetheless. Another related problem is identifiying and grouping multiple disconnected regions moving in similar motions, such as a flock of geese. Early approaches focused on measuring motion of either the boundaries or the interior but seldom both in unison.For several years now, attempts have been made to include spatial coherence terms into algorithms for 2 and 3-D motion recovery, as well as motion boundary estimation. (Spatial Coherence for Visual Motion Analysis, W.James McLean, page : - (preface))

Motion Analysis (New)(Ergonomics)

Analysis of human movement has a rich history dating back to the original cinephotographic technique used by pioneers in the field. Methods have progressed through strobe photography of sequences in skilled movements video analysis with pause facilities to digital video recording, fast-film analysis, and synchronized cameras for analysis of motion in three dimensions. The technologies available are continually being updated, and the asssociated software has eliminated the drudgery of data extraction using the earlier methods.
 Contemporary methods incorporate specialized transducers and automatic analyzers with built-in calibration systems. The systems have fast-frame and pause facilities that allow sport scients to analyze movements and skills in their minutie. Examples include studies of the golf swing, tennis serve, long-jump take offf, and pole vault. It is possible also to perform accessory monitoring-for example, using alactromyography or force analysis- to supplement the information observed from motion analysis. Where cost is an issue for prospective users, video -based systems that allow qualitative analysis of motion provide a practical alternative to three dimensional biomechanical analysis.

(Thomas Reilly, Ergonomics in sport and physical activity: anhancing performance, page 105-106)

The new one is better.

Laminate(Previous):
laminates used in PCB manufacture,whether rigid or flexible are created in two primary forms:single
clad and double clad laminates.they are also produced in a number of different thicknesses to faciliate the
manufacture of pcb with different thickness requirements and for the construction of multiplayer circuits,the
laminate is commonly referred to as a core material.

( Charles A. Harper,Electronic materials and processes handbook,p.13 ) 

Laminate(New):(Material)
Consider the  term 'balnced' that is often used to describe a laminate. One prominent definition is : ''Balancede composite - A composite laminate whose layup is symmetrical with relation to be midplane of the laminate or symmetrical with respect to in-plane shear''[7]. That definition is certainly as clear as mud!
(DEStech Publications, Incorporated,Proceedings of the American Society for Composites, p.138)

The previous one is better.