Fatih Tuncay KOLÇAK - 080080162

Demand Management ( New ) ( Better ) ( Economical Policy ) - 1. week

Demand management is the use of monetary and fiscal policy to stabilize the level of income around a high average level. Fiscal policy is the set of decisions the government makes about taxation and spending. Through such decisions, the government can shift the IS schedule. Monetary policy is the corresponding set of decisions about the monetary supply. Monetary policy can shift the LM curve. Although fiscal decisions will determine the government’s budget deficit, it is not essential to finance the deficit by printing money. The government can also sell bonds and borrow from private sector. Hence, if it chooses, the government can pursue independent monetary and fiscal policies.

Thus, if pessimism about the future leads the private sector ( firms and households ) to spend less, the government can use an expansionary fiscal policy to shift the IS schedule upwards, an expansionary monetary policy to shift the LM curve to the right, or some combination of these two policies. Nevertheless, monetary and fiscal policy are not interchangeable. They affect aggregate demand throuh different routes and have different implications for the composition of aggregate demand.

( Begg, David; Fischer, Stanley; Dornbusch, Rudiger, Economics fifth edition, pg. 415-416 )

Demand Management ( Previous )

A first basic consept to grasp is that demand management embodies much more than just developing a forecast of demand. According to Philip Kotler a respected thought leader on marketing management , demang management involves influencing the level , timing , and composition of demand. Demand management consists of the following elements:

Planning Demand , Communicating demand , Influencing demand , Managing and prioritizing demand

(Demand management best practices ; Colleen Crum,George E. Palmatier , pg . 10-11 ; Özgür Cebeci 030060158)

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Elastomers ( New ) ( Better ) ( Material ) - 1. week

Conventional rubbers are members of the polymer family in that they consist of long chain-like molecules. These chains are coiled and twisted in a random manner and have sufficient flexibility to allow the material to undergo very large deformations. In the green state the rubber would not be able to recover fully from large deformations because the molecules would have undergone irreversible sliding past one another. In order to prevent this sliding, the molecules are anchored together by a curing ( vulcanisation ) process. Thus the molecules are cross-linked in a way similar to that which occurs in thermosets. This linking does not detract from the random disposition of the molecules nor their coiled and twisted nature so that when the rubber is deformed the molecules stretch and unwind but do not slide. Thus when the applied force is removed the rubber will snap back to its original shape.
Vulcanised rubbers possess a range of very desirable properties such as resilience, resistance to oils, greases and ozone, flexibility at low temperatures and resistance to many acids and bases. However, they require careful (slow) processing and they consume considerable amounts of energy to facilitate moulding and vulcanisation. These disadvantages led to the development of thermoplastic rubbers (elastomers). There are materials which exhibit the desirable physical characteristics of rubber but with the ease of processing of thermoplastics.

( Crawford, R.J. Plastics Engineering 2nd edition, Pergamon press, pg. 9-10 )

Elastomers ( Group : Material ) ( Previous )

New and better answer because this one is simple to understand with the examples. 

Elastomers are long-chain polymers above their glass-transition temperature, Tg. The covalent bonds that link the units of the polymer chain remain intact, but theweaker Van derWaals and hydrogen bonds that, below Tg, bind the chains to each other, have melted. This gives elastomers unique property profiles: Young’s moduli as lowas 10_3GPa (105 time less than that typical ofmetals) that increase with temperature (all other solids show a decrease), and enormous elastic extension. Their properties differ so much from those of other solids that special tests have evolved to characterize them.This creates a problem: ifwewish to select materials by prescribing a desired attribute profile (as we do later in this book), then a prerequisite is a set of attributes common to allmaterials.Toovercomethis, we settle on a common set for use in the first stage of design, estimating approximate values for anomalies like elastomers. Specialized attributes, representative of one family only, are stored separately; they are for use in the later stages.

( ASHBY, M. F. (2005). The families of engineering materials. Material selection in mechanical design 3rd (p.30 ). )

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Reinforced Plastics ( New ) ( Better ) ( Material ) - 1. week

It was mentioned earlier that the stiffness and strength of plastics can be increased significantly by the addition of a reinforcing filler. A reinforced plastic consists of two main components ; a matrix which may be either thermoplastic or thermosetting and a reinforcing filler which usually takes the form of fibres. In general, the matrix has a low strength in comparison to the reinforcement which is also stiffer and brittle. To gain maximum benefit from the reinforcement, the fibres should bear as much as possible of the applied stress. The function of the matrix is to support the fibres and transmit the external loading to them by shear at the fibre/matrix interface. Since the fibre and matrix are quite different in structure and properties it is convenient to consider them seperately.

( Crawford, R.J. Plastics Engineering 2 nd edition, Pergamon press, pg. 80 )

( Previous )

Reinforced Plastics:An important class of composites are reinforced plastics that consist of fibers are dispersed in a discontinious manner within a continious matrix of polymer.Reinforced plastics with more than one type of fiber are said to be hybrid.The commonly used fiber materials include glass,graphite,boron nylon,silicon nitride,silicon carbide etc.(Rapid prototyping : laser based and other technologies,Patri K. Venivinod,Weiyin Ma,p:52)

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Robot Safety ( New ) ( Better ) ( Safety Instructions ) - 1. week

Industrial robots are moving machines, and the safety hazards associated with moving machinery, and their electric power supplies have long been recognized. The robot, however, presents some unique additional safety problems that have to be addressed. These arise from the following characteristics:

1.The robot arm and end effector move within a work envelope volume very much larger than the robot’s own base, the only exception to this being the cartesian gantry type robot. This large danger zone within which an arm with possibly six degrees of freedom can move around in, can be difficult for the inexperienced passer-by to anticipate.

2.Due to the fact that the robot moves in response to commands from its controller it can appear to the casual observer to move both spontaneously and unpredictably. This is especially dangerous when a delay has been built into the program and the robot is immobile while awaiting a command. In this case the robot, after a period of quiescence, may suddenly burst into activity.

3.The programmability of the robot means that the integrity of the control system hardware and software is extremely important. Faults in hardware or errors in programming can cause erratic, unexpected behaviour.

4.The fact that the heavier duty robots are powerful, massive and fast makes them more dangerous. When a robot is designed for moving heavy loads with precision it is currently constructed with strong inelastic materials to prevent deflection. Also the actuators, drivers and transmission components will often be heavy. When this is considered in conjuction with what may be at the end of the arm, e.g. a spot welding gun or large gripper holding a steel billet, it is evident that a moving robot is a force to be reckoned with.
( Mair, Gordon M. Industrial Robotics, pg. 290 )

Robot Safety: ( Previous )
Depending on the size of the robot's work envelope, speed, and proximity to humans, safety considerations in a robot environment are important, particularly for programmers and maintenance personel who are in direct physical interaction with robots. In addition, the movement of the robot with respect to other machinery requires a high level of reliability in order to avoid collisions and damage to equipment. Its material-handling activities require the proper securing of raw materials and parts in the robot gripper at various stages in the production line.
(Kalpakjian S., Schmid S.R., Manufacturing Engineering and Technology,5th Edition, pg.1171)
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Mechanization ( New ) ( Manufacturing ) - 1. week

This means that something is done or operated by machinery and not by hand. Feedback is not provided, thus one deals with open-loop control. An example would be the use of a cam to move the cross slide. A different cam would have to be used ( or its position reset ) if a cylinder of different diameter had to be machined.

( Schey, John A. Introduction to Manufacturing Processes, pg. 34 )

Mechanization ( Previous ) ( Better )
In improving productivity, the important elements have been mechanization, automation, and control of a manufacturing equipment and systems. Mechanizationcontrols a machine or process with the use of various mechanical, hydraulic, pneumatic, or electirical devices. In spite of its benefits, in mechanized operations the worker is still involved in a particular process directly and must check each step of a machine's performance. (Manufacturing Engineering and Technology, Serope Kalpakjian, p1145)