فهرست مطالب y. shokri

In this paper, modeling and analysis of equipment arrangement from an exergoeconomic approach to produce required heat and power of a total site is determined. By using a modified Iterative Bottom-to-Top Model (IBTM) as a new cogeneration targeting method, cogeneration of heat and power potential to design utility system of a total site is estimated and fit to it, superheated temperature of steam levels, power generation of steam turbines between levels, flow rate of passing steam through turbines, amount of boiler heat load and boiler required fuel flow rate are calculated. First, different scenarios of steam turbines arrangements are introduced that are investigated from exergoeconomic approach. Also in suggested plans to produce extra power in case study, gas turbine system has maximum exergy efficiency, minimum exergy destruction, minimum total capital cost rate and exergy destruction cost rate rather than condensing turbine plan. Hence, the selected scenario of back pressure steam turbines arrangement beside the gas turbine system were introduced as the optimum system of heat and power cogeneration system in total site for this case study from an exergoeconomic approach.

Introduction &

Recently، it has been suggested that there might be an association between oral diseases such as dental caries، as well as periodontitis and general health. Re-garding the fact that albumin is an indicator of general health، the aim of the present study was to evaluate the relationship of salivary albumin concentration with dental caries.

In this descriptive-analytical study 108 patients aged 13-19 years old who had teeth caries were placed in 3 groups with mild، moderate and severe dental caries according to their DMFT value (n=36). Five ml of unstimulated saliva were taken from each participant via Navazesh method and their albumin concentrations were assessed by nephelometery method. Data were analyzed by t-test and ANOVA.

The mean concentration of salivary albumin in three experimental groups was 84. 442±42. 915، 97. 964±66. 717 and 89. 850±33. 003، respectively. ANOVA showed that the difference among the mean values was not significant (P=0. 09) but the relationship between salivary albumins and sex was significant (P=0. 009).

According to the results of the present study there was no significant relationship between albumin and dental caries in 13-19 year old individuals.