Machine-Related Problems

Lubricating-film instability is the dominant failure mode for sleeve bearings. This instability is typically caused by eccentric, or off-center, rotation of the machine shaft resulting from imbalance, misalignment, or other machine or process-related problems. Figure 44.48 shows a Babbitt bearing that exhibits instability. 

The earliest due date nde, which schedides the jobs in increasing order of their due dates, minimizes the maximum lateness on a single machine (see Jackson 1955), that is, l f , , as well as in a proportionate flow shop, that is, Fm py = pj L. However, it does not provide an optimal solution for other due date-related problems, such as l 27j. Instances of l 27j with... 

Medical devices such as ventilators, blood chemistry analyzers, patient monitors, infusion pumps, and kidney dialysis machines often have various types of user-interface design-related problems. These problems can negatively affect usability and appeal of a medical device. The following guidelines address these user-interface design problems, in turn reducing device user-interface-related errors [8]. 

The difficirlty of extracting GPS-related human machine interaction problems has prevented the identdication of the relevant issues in today s aviatioa The combined incident and accident study presented here shottld distinguish the issues that initially need our atterrtion and may prevent an increase in GPS-related incidents and possible accidents. On the basis of the theory on human/machine interaction and the previous studies on GPS utihzation in aviation, it is expected that incidents and accidents reveal issues of training and system design. Incident analysis should aid in the prevention of accidents, particirlarly since incidents can be considered a precursor of an accident and may develop into an accident without intervention. 

Mechanical failures may occur for a number of reasons. Some are induced by cavitation, hydraulic instability, or other system-related problems. Others are the direct result of improper maintenance. Maintenance-related problems include improper lubrication, misalignment, imbalance, seal leakage, and a variety of others that periodically affect machine reliability. 

Another problem could also result in excessive imbalance-related vibration even though the ISO standards were met. The ISO standards call for a balancing grade of G6.3 for components such as pump impellers, normal electric armatures, and parts of process plant machines. This results in an operating speed vibration... 

In principle, the task of solving a linear algebraic systems seems trivial, as with Gauss elimination a solution method exists which allows one to solve a problem of dimension N (i.e. N equations with N unknowns) at a cost of O(N ) elementary operations [85]. Such solution methods which, apart from roundoff errors and machine accuracy, produce an exact solution of an equation system after a predetermined number of operations, are called direct solvers. However, for problems related to the solution of partial differential equations, direct solvers are usually very inefficient Methods such as Gauss elimination do not exploit a special feature of the coefficient matrices of the corresponding linear systems, namely that most of the entries are zero. Such sparse matrices are characteristic of problems originating from the discretization of partial or ordinary differential equations. As an example, consider the discretization of the one-dimensional Poisson equation... 

The chemical applications on coffee pose problems that can be solved to the mutual advantage of the coffee grower and the manufacturer of spray machines and chemicals. The problems cannot be left solely to either party. Through the service of technical men working in the tropics, the manufacturer will need to carry on close relations with the field. The evolution of spray science in the tropics, under condi-... 

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