In this paper, the renewal process, for the homogeneous and non-homogeneous Poisson process as well as Kijima models, are reviewed. Given the distribution function of time of the successive repair time's form, the corresponding cost function is defined. Then, using the failure function the optimal time of repair is achieved.

Companies must determine the replacement time of machine parts correctly since it a, ects their production costs and e, ciencies. In this respect, the objective is to determine the most appropriate replacement time to minimize cost per unit. This study proposes developing a hybrid Arti, cial Neural Network (ANN)-Genetic Algorithm (GA) model to predict replacement time without using a cost model. At , rst, a replacement cost model is developed to calculate replacement times to use in training the neural network. Nevertheless, the cost model needs complex mathematical calculations. GA is used instead of the cost model to determine replacement time and thus, to achieve fast learning for the neural network. The hybrid ANN-GA model was applied to predict replacement time of bladder in tire manufacturing. Furthermore, ANN and GA models, which were developed to increase the prediction accuracy of the hybrid model, were used. The hybrid ANN-GA model presented a better solution according to the performance statistics than the other ANN and GA models. The values indicate that the hybrid model is in good agreement with the cost model. Thus, it is recommended that the hybrid model be used instead of the cost model.

The approach and attitude of the contemporary human being about crime, and punishment of criminals has undergone serious change and transform that is mainly the result of change of human attitudes towards his role, position, rights and generosity. This study evaluates the theoretical position of some Islamic punishments (Hodoud and Tazirat) in the absence of innocent Imam (peace be upon him). The author believes that the change and replacement of the authorized and non-authorized legal penalties with other conventional penalties or reform methods is possible from the point of view of religious rules and principles and is a historical necessity regarding time requirements. The innovative aspect and distinctive feature of this article compared with other articles related to it is the acceptance of the change and replacement even in the case of legal authorized penalties.

Pipes burst and leakage rates in water distribution networks are growing with increasing of pipes age. Therefore, pipe rehabilitation and replacement programs would be necessary during the pipes life time. This is a complicated problem in which budget restriction has an important impact. This paper introduces a simple model to determine the best time for leak detection and pipe replacement programs using pipes break records. Assuming a linear relationship between pipes break rate with time, the operation cost for three different steps of: pipe repair, leak detection and pipe replacement are evaluated and the best time for commencing of each scenario is calculated. To highlight advantages of the proposed methodology, it is applied to a pipe network in one of the Iranian cities. At first pipes break records are gathered for a period of six months using a standard format. Then the best time for leak detection and replacement programs are determined and sensitivity of the results to different parameters is evaluated. It can be concluded that the proposed methodology produces a powerful tool to be used in water distribution networks and help decision makers to choose the best option considering budget restrictions.

The decision to replace an item of farm machinery can be made because of cost minimization, reliability, new technology, need for capacity, obsolescence, wear and tear, and has a vital role in machinery management. In other words, most capital goods have an optimal lifespan and replacing machinery at a more or less than optimal age could significantly affect profitability. Therefore, this study aims to investigate the optimal replacement time under certainty condition using four methods for combine harvester in Fars province. According to the first method, the most appropriate time for combine harvester is the year in which the accumulated annual repairs, depreciation and maintenance cost per working hour is minimum. The second method considers the optimal replacement time for combine to be the year in which the initial value of the machine and accumulated annual repairs and maintenance cost per working hour is minimum. The third method for economic life determination is based on minimizing the accumulated average total cost per working hour and according to the fourth method, the most appropriate time for combine harvester replacement is considered to be the year in which the accumulated net income is maximum. By a stratified random sampling method, 160 John Deere 955 combine which is dominant in Fars province were chosen for interview to collect the technical and economic data and other needed information. The results showed that the optimal replacement time of a John Deere 955 combine under certainty condition were 16, 18, 14 15th year of its productive life with 18786, 21291, 16076, 17424 working hours respectively based on the results of four relevant methods.

In order to investigate the effect of inorganic selenium replacement with organic selenium from Spirulina algae on performance and breast meat quality of broilers, a total of 160 one-day-old chicks were used in a completely randomized design with four treatments, eight replicates and five birds per each replicate. The sources of selenium used included sodium selenite and organic selenium from Spirulina algae which were replaced at two levels of 50 and 100 percent. The organic selenium was produced by the culture of Spirulina algae and its enrichment with selenium. The selenium content of different treatments was measured by ICP-Mass method. In this experiment, the feed intake and body weight gain parameters were measured weekly and feed conversion ratio was calculated. At 42 day of age, one bird was slaughtered from each replicate and the weight of carcass ready to cook was measured. The breast meat was sampled for measurement of pH and selenium storage. The results showed that it was not observed any significant difference in performance traits and ready to cook carcass percentage among different treatments. There was no significant difference in breast muscle pH at 0 and 24 hours after slaughtering. The amount of selenium deposited in breast muscle of birds fed organic selenium had significant increase when compared with other treatments (P<0.05). Generally, the results of this study showed that 100% replacement of sodium selenite with organic selenium from Spirulina algae led to increase in breast muscle selenium deposition without reduction in bird performance.

OBJECTIVES: To evaluate the effect of two simultaneous protocols in reducing recovery time and assessment of adverse effects of different fluid replacement therapy in management of diabetic ketoacidosis.MATERIALS AND METHODS: In this randomized clinical trial study, two standard protocols were chosen to evaluate recovery time and incidence of DKA complications.RESULTS: 18 subjects who had severe diabetic ketoacidosis were included in our analysis. In the course of treatment, hypokalemia happened in 5 cases in protocol 1 and 4 cases in protocol 2. Hypernatremia occurred in 2 cases of protocol 1 and 4 cases in protocol 2. Hyponatremia occured in 4 cases of protocol 1 and 2 cases in protocol 2. The mean recovery time of acidosis in protocol 1 was 21±5.9 (mean±SD) hours and 23±10.9 hours in protocol 2. None of them had any signs and symptoms of cerebral edema or mental status deterioration in the course of treatment.CONCLUSION: According to our study, different volume deficit calculated as a base for dehydration which was replaced in different times and in a similar clinical setting, had not added any risk of complications during the treatment. Also no significant differences were found in recovery time related to the different fluid replacement protocols. We also found that complication of therapy increases with the severity of diabetic ketoacidosis.

Efficiency and performance of agricultural machinery, including combine is quantity and quality of work per hour or per hectare of harvest. The combine grows older there is a tendency for economic efficiency and performance to decrease. So, there is no economical performance to use that anymore and it must be replaced with a new combine. The decision to replace an item of farm machinery can be made because of cost minimization, reliability, new technology, need for capacity, obsolescence, wear and tear. Therefore the optimal replacement time for combine in order to increase its performance is one of the most important objects of combine management. The decision to replace an item of farm machinery can be made because of cost minimization, reliability, new technology, need for capacity, obsolescence, wear and tear; and has a vital role in machinery management. In other words, most capital goods have an optimal lifespan and replacing machinery at a less or more than optimal age could significantly affect profitability. According to this study aims to investigate the optimal replacement time for combine harvester in Fars province. To this end, introduces stochastic elements into the models to show if uncertainty about future costs affects the replacement decision. Thus, a decision tree was drowning for each three year of life and it was then analyzed using stochastic dynamic programming. By a stratified random sampling method, 160 John Deere 955 combine which is dominant combine in Fars province were chosen for interview to collect the technical and economic data and other needed information. The results indicated that, the most appropriate time of replacement under uncertainty condition about future cost for the combine was 17th year of its life.