This paper presents a new approach using Witness Simulation in combating issues related to maintenance within the existing manufacturing facility. Currently, maintenance is a key issue as many machines breakdown due to every day wear and tear as well as the age of the machine itself. This causes bottlenecks within the entire production system as the schedules of production is disturbed and further backlogs are developed. Also, when machines breakdown there seems to be very little communication from one end to another ie parts are needed for the repair of many of the machines, for example, it is very common for the rotary kiln to come to a halt due to increased temperature and different quantities of a mixture of materials. In order to fix the problem and move back on schedule the maintenance team uses certain materials ie same materials, all the time. However, due to not having an adequate stock control system and the lack of communication many a times, parts are not readily available and hence the team wait further until parts arrive at the facility. This paper will demonstrate how all of the above problem areas can be adhered to via the use of adopting a simple automated response system using Witness Simulation. The demonstration will be based on a single machine for testing purposes to ensure efficiency that can later be applied to the entire system as a whole.

This paper explores the use of Bayesian network modeling of machine breakdowns within a cement manufacturing plant. The Bayesian network modeling is introduced using Hugin software and then implemented into a Witness Simulation model using historical data, expert knowledge and opinions. The models simulate 3 parameters of the machine based on life consumption and usage of each parameter, the developed Witness model produces a probability failure rate based on these parameter usages. The failure probability developed by Witness is implemented using the Chain Rule; this is compared with the probability for failure based on the Bayesian network model. This enables the user to see the probability of failure developed by the implementation of the chain rule and Witness based on the parameter usage, on a live streaming fashion as the model is running. This can be used as a decision making tool for management to consider machine maintenance affectively based on parameter usage.

This paper explores the value of stochastic simulation as a tool for predicting current or future reliability of machinery, it helps to understand machine failures by using confidence levels developed through replications and exploring the changes that occur. A stochastic simulation model has been constructed representing a crusher machine with in a cement manufacturing plant. The crusher machine has three parameters; namely those are drill head, dusting and lubrication. The consumption of these parameters results in the development of a probability of failure for the machine using Bayes theory.

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ABSTRACT

This study reviews the Public Transportation (PT) Systems and the opportunities and requirements applied

in Libya. Beginning with the definition of public transport systems and their functions and areas of applied and

advanced systems for public transport and advanced systems for traffic management, systems and operations of

transport vehicles and advanced systems to control private vehicle and safety, with a discussion of the

importance of each of them, this paper discusses the requirements of the application of Bus Rapid Transit

(BRT) systems in mass with focus placed on the importance of developing an outline plan for the public

transport systems. The concept master plan and the options available in Tripoli shall be discussed to develop its

map of structural public transportation systems and recommend consideration of the possible adoption of a map

structure developed in the advanced countries and some developing countries in this area, with their adaptations

depending on the circumstances of Tripoli. It also concludes with the need to establish a permanent institution

representing the parties involved, including the public sectors, academia; and vested in the institutions

responsible for managing, directing, and the preparation of a strategic plan for public transport systems,

including the development of the master plan for those systems. The study recommends starting with pilot

projects carefully selected by an explanatory expansion in the application.

Key words: public transport system, bus rapid transit, safety, control private vehicles, traffic management,

Tripoli.

ABSTRACT

This study reviews the Public Transportation (PT) Systems and the opportunities and requirements applied

in Libya. Beginning with the definition of public transport systems and their functions and areas of applied and

advanced systems for public transport and advanced systems for traffic management, systems and operations of

transport vehicles and advanced systems to control private vehicle and safety, with a discussion of the

importance of each of them, this paper discusses the requirements of the application of Bus Rapid Transit

(BRT) systems in mass with focus placed on the importance of developing an outline plan for the public

transport systems. The concept master plan and the options available in Tripoli shall be discussed to develop its

map of structural public transportation systems and recommend consideration of the possible adoption of a map

structure developed in the advanced countries and some developing countries in this area, with their adaptations

depending on the circumstances of Tripoli. It also concludes with the need to establish a permanent institution

representing the parties involved, including the public sectors, academia; and vested in the institutions

responsible for managing, directing, and the preparation of a strategic plan for public transport systems,

including the development of the master plan for those systems. The study recommends starting with pilot

projects carefully selected by an explanatory expansion in the application.

Key words: public transport system, bus rapid transit, safety, control private vehicles, traffic management,

Tripoli

Given the pressing need for new antiprotozoal drugs without cross-resistance with current (failing) chemotherapy, we have explored 3-tridecylpyridinium alkaloids (3TPAs), derivatives of viscosamine, as antiparasitic agents. We have developed a simple synthetic route toward viscosamine and related cyclic and linear monomers and oligomers. Evaluation for cytotoxicity on the protozoan parasites Trypanosoma brucei, Leishmania spp., and Plasmodium falciparum revealed several 3TPAs with antiprotozoal activity in the nanomolar range. Their promising selectivity index in vitro prompted us to study the dynamics of cytotoxicity on trypanosomes in more detail. Parasites were killed relatively slowly at therapeutically safe concentrations, in a process that did not target the cell cycle. Clearance of T. brucei cultures was observed at drug concentrations of 1–10 μM.

The higher strength 7xxx aluminum alloys exhibited low resistance to stress corrosion cracking (SCC) when aged to the peak hardness (T6 temper). The overaged alloys (T7 temper) developed to enhance the SCC with loss in the strength of the alloy. Recently, retrogression and re-aging (RRA) heat treatments are used for improving the SCC behavior for alloys in T6 tempers such as 7075, 7475 and 8090. In this study, an application of retrogression and re-aging heat treatment processes are carried out to enhance toughness properties of the 7079-T651 aluminum alloy, while maintaining the higher strength of T651-temper. The results of charpy impact energy and electrical conductivity tests show a significantly increases in absorbed energy and electrical conductivity values, when the alloys are exposed to various retrogression temperatures (190, 200, 210°C) and times (20, 40, 60 minutes), and then re-aged at 160°C for 18 hours.

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