scholarly journals Optimal Profit Analysis of Machine Repair Problem with Repair in Phases and Organizational Delay

2020 ◽  
Vol 6 (1) ◽  
pp. 442-468
Author(s):  
Chandra Shekhar ◽  
Praveen Deora ◽  
Shreekant Varshney ◽  
Kunwar Pal Singh ◽  
Dinesh Chandra Sharma
Keyword(s):  
Finite Number ◽  
Size Distribution ◽  
Design Parameters ◽  
Queue Size ◽  
Machine Repair ◽  
Critical Design ◽  
Server Breakdown ◽  
Profit Analysis ◽  
Recursive Matrix ◽  
Warm Standby

In this article, we study machine repair problems (MRP) consisting of the finite number of operating machines with the provisioning of the finite number of warm standby machines under the care of a single unreliable server. For the machining system’s uninterrupted functioning, an operating machine is immediately replaced with the available warm standby machine in negligible switchover time whenever it fails. The concept of threshold vacation policy: N-policy is also considered. Under this vacation policy, the server starts to serve the failed machines on the accumulation of a pre-specified number of failed machines in the system. The server continues until the system is empty from the failed machines; after that, the server goes for vacation. The notion of an organizational delay, server breakdown, and repair in multiple phases is also conceptualized to build the studied model more realistic. The recursive matrix method is used to find steady-state queue size distribution, and subsequently, various system performance measures are also developed to validate the studied model. The optimal analysis has been performed to identify the critical design parameters for the governing model. The state-of-the-art of the present study is its mathematical modeling of the multi-machine stochastic problem with varied limitations and strategies. The methodology to obtain queue size distribution, optimal design parameters, is beneficial for dealing with other complex and sophisticated real-time machining problems in the service system, computer and communication system, manufacturing and production system, etc. The present problem is limited to fewer machines, which can be extended to more machines with different topologies with high computational facilities.

Effects of Process and Design Parameters on Granule Size Distribution in a Continuous High Shear Granulation Process

2017 ◽  
Vol 12 (4) ◽  
pp. 283-295 ◽  
Author(s):  
Wei Meng ◽  
Sarang Oka ◽  
Xue Liu ◽  
Thamer Omer ◽  
Rohit Ramachandran ◽  
...  
Keyword(s):  
Size Distribution ◽  
Granule Size ◽  
Design Parameters ◽  
High Shear ◽  
Granulation Process

Relations Among Moments of Waiting Time and Queue Size Distribution in Bulk Queueing Systems

1987 ◽  
Vol 36 (1-2) ◽  
pp. 63-68
Author(s):  
A. Ghosal ◽  
S. Madan ◽  
M.L. Chaudhry
Keyword(s):  
Size Distribution ◽  
Waiting Time ◽  
Queueing Systems ◽  
Queueing Models ◽  
Queue Size ◽  
Different Types

This paper brings out relations among the moments of various orders of the waiting time and the queue size in different types of bulk queueing models.

Design Quality and Reliability Through Technology Readiness

1989 ◽  
Author(s):  
J. Fox
Keyword(s):  
Product Launch ◽  
Design Parameters ◽  
Technology Readiness ◽  
Design Quality ◽  
Critical Design ◽  
Early Stages ◽  
Product Delivery ◽  
Quality And Reliability ◽  
The Relationship

Abstract This paper discusses the relationship between the growth of reliability in the early stages of a product delivery process and Technology Readiness, and describes the importance of ‘ready’ technologies if product launch schedules are to be achieved. Technology Readiness itself is defined and the enablers for it are identified. A process which has been developed is described, and some proposals for tracking and managing progress are made. Finally, the importance of critical design parameters both in the development of technologies and in understanding technology capabilities are described fully.

Steam Turbine Overspeed Scenarios: Comparison Between API Energy Method and Dynamic Simulation

2021 ◽  
Author(s):  
Fabrizio Piras ◽  
Federico Bucciarelli ◽  
Damaso Checcacci ◽  
Filippo Ingrasciotta
Keyword(s):  
Design Parameters ◽  
Steam Turbines ◽  
Analysis Method ◽  
Design Constraint ◽  
Rotating Speed ◽  
Critical Design ◽  
Operating Stress ◽  
Technological Challenge ◽  
Rotor Dynamic ◽  
Peak Value

Abstract In turbomachinery applications the possibility to reduce size and costs of main flow-path components, by increasing shaft rotating speed, has always been appealing. The technological challenge in increasing this power density capability is typically related to performance prediction, to operating stress in blades and shafts, as well as to the need for a more accurate rotor-dynamic analysis. Yet another aspect, often reduced to standard assessments in less demanding applications, is related to the analysis of overspeed scenarios where, following a sudden loss of load and/or driven inertia, the turbomachine shall maintain its mechanical integrity. Especially in steam turbines applications, where the behavior of the machine is strongly affected by the plant conditions, valves intervention time and connected volumes, the reduction of the rotor inertia, against comparable power, may produce overspeed scenarios that can become a primary design constraint and, if overlooked, may have both availability and safety implications. In this paper several approaches to the analysis of overspeed scenarios are discussed, with increasing level of detail. The energy-based overspeed analysis method, as required by API612, is first discussed against practical design cases. A more accurate dynamic model is then presented, and its results compared with those of the energy-based approach. Finally, the sensitivity analysis of the overspeed peak value with respect to critical design parameters is discussed. With respect to previous works, mostly based on load rejection scenarios, the main focus is on the scenario of sudden coupling loss.

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