030070104 Cebrail Yıldırım 10th week

Malleable iron(first&best) [Material]

Malleable iron is an iron-carbon alloy in which the carbon exists as nodular graphite. Malleable iron is formed from white iron by heat treating. The result is an alloy with much improved fracture toughness and increased elastic modulus (compared to gray cast iron). the hardness, of course, is reduced. This material resembles steel in mechanical properties and yet can be fabricated by casting - a low cost advantage over steel. Heat treatment required to achieve the nodular structure however, is long and expensive

(William A. Glaeser, Materials for Tribology, pg.90)

There is no previous definition. 

Material Property Chart (First&best) [Chart]

Material properties limit performance. We need a way of surveying them, to get a feel for the values design-limiting properties can have. One property can be displayed as a ranked list or bar-chart. But it is seldom that the performance of a component depends on just one property. Almost always it is a combination of properties that matter: one thinks, for instance, of the strength-to weight ratio or the stiffness-to-weight ratio that enter light-weight

design. This suggests the idea of plotting one property against another, mapping

out the fields in property-space occupied by each material class, and the sub-fields occupied by individual materials. The resulting charts are helpful in many ways. They condense a large body of information into a compact but accessible form; they reveal correlations between material properties that aid in checking and estimating data. The engineering properties of materials are usefully displayed as material selection charts. The charts summarize the information in a compact, easily accessible way, they show the range of any given property accessible to the designer and they identify the material class associated with segments of that range. By choosing the axes in a sensible way, more information can be displayed: a chart of modulus E against density _ reveals the longitudinal wave velocity; a plot of fracture toughness K1C against modulus E shows the toughness; a diagram of thermal conductivity _ against diffusivity, a, also gives the volume specific heat _Cv; strength against modulus, E, shows the energy-storing capacity , and there are many more.

(Micheal F. Ashby, Materials Selection in Mechanical Design, 3^rd ed., pg 45,77)

Corrective action and preventive action(first&best) [Action]

The manufacturer is responsible for the implementation and maintenance of a QMS which en-ables their organization to provide safe and effective medical devices meeting customer and regulatory requirements. A nonconformity  is a non fulfillment of a requirement. It is important to under-stand that requirements may relate to product, process or the QMS.

When a nonconformity is identified, the manufacturer will determine the significance, the associated risk and the potential for recurrence.  Once these have been determined the manufacturer may decide the nonconformity has little associated risk or is unlikely to recur. In such cases the manufacturer may decide only to carry out a correction. So, corrective action is to eliminate the cause of a detected nonconformity or other undesirable situ-ation

There can be more than one cause for nonconformity  Corrective action is taken to prevent recurrence whereas preventive action is taken to prevent occurrence  There is a distinction between correction and corrective action  Preventive action is to eliminate the cause of a potential nonconformity or other undesirable situation  There can be more than one cause for nonconformity  Preventive action is taken to prevent occurrence whereas corrective action is taken to prevent recurrence.

(Study Group 3, Quality management system –Medical Devices – Guidance on corrective action and preventive action and related QMS processes, Global Harmonization Task Force, 2010)

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Operation scheduling(first&best) [Scheduling]

Operation scheduling (OS) is an important task in the high-level synthesis process. An inappropriate scheduling of the operations can fail to exploit the full potential of the system. In this chapter, we try to give a comprehensive coverage on the heuristic algorithms currently available for solving both timing and resource constrained scheduling problems. Besides providing a broad survey on this topic, we focus on some of the most popularly used algorithms, such as List Scheduling, Force-Directed Scheduling and Simulated Annealing, as well as the newly introduced approach based on the Ant Colony Optimization meta-heuristics. We discuss in details on their applicability and performance by comparing them on solution quality, performance stability, scalability, extensibility, and computation cost.Moreover, as an application of operation scheduling, we introduce a novel uniformed design space exploration method that exploits the duality of the time and resource constrained scheduling problems, which automatically constructs a high quality time/area tradeoff curve in a fast, effective manner. Operation scheduling methods can be further classified as static scheduling and dynamic scheduling [40]. Static operation scheduling is performed during the compilation of the application. Once an acceptable scheduling solution is found, it is deployed as part of the application image. In dynamic scheduling, a dedicated system component makes scheduling decisions on-the-fly. Dynamic scheduling methods must minimize the program’s completion time while considering the overhead paid for running the scheduler.

(Philippe Coussy,Adam Morawiec, High-Level Synthesis: From Algorithm to Digital Circuit, pg. 231

There is no previous definition. 

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Grub screw(first&best) [Machine Element]

Set-screws are similar to bolts, however they are threaded till the end. They are often used to prevent relative motion between two parts. The heads of set-screws driver slots or they can be turned by wrenches or spanners. Grub screw is a kind of set-screw which does not have any head. These are used and locking screws, typically in mounting keys in keyways. The set-screw can have different ends and they can be selected depending on its use.

 

 

(Farazdak Haideri,Machine Drawing and Computer Graphic, pg. 48)

There is no previous definition.