Background &Aim: Erosion has been defined as the irreversible loss of dental hard tissue by a chemical process not involving bacteria. Dental erosion is an important cause of tooth tissue loss in both children and adults. Acids of intrinsic and extrinsic origin (gastric juice and acidic food staffs, beverages) are thought to be the main etiologic factors for dental erosion. The reported incidence of tooth erosion caused by soft drinks has been increasingly documented because soft drinks consumption has increased dramatically over two decades. The aim of this study was to evaluate the PH and TA of some of the Iranian carbonated soft drinks.Methods and Materials: An experimental Lab study was designed in Kerman for controlling PH and Titratable Acidity (TA) of Iranian carbonated drinks cola, orange and Lemon lime. Twenty - three kinds of drink were collected from three different groups (cola, orange, lemon lime) and their PH and TA were assessed 10 days, 2 months and 4 months after their production. Data were analyzed with SPSS, paired T test and ANOVA.Results: Analysis of data showed PH of soft drinks was 2.5-3. PH of cola drinks was less than other drinks (P<0.05). TA of orange drinks was more than other drinks but there wasn't any significant different between groups of drinks. TA of soft drinks was 0.11-0.14.Conclusion: Chemical tests indicate that all soft drinks in this study have approximately suitable PH & TA.

In order to investigate the effect of operational parameters on corrosion resistance of trication zinc phosphate coating on iron steels substrate in dip system, a series of experiments were done in laboratory. After salt spray test, a test that indicates the corrosion resistance of a painted film, the following results were obtained: for free Acidity, when it was gradually increased, corrosion resistance of coating increased so that in a certain range, it achieved the best resistance; when it was further increased, the corrosion resistance decreased. For total Acidity, it was observed again that within a certain range of total acid, the corrosion resistance of coating was high enough and out of this range decreasing of resistance was observed. As far as the time is concerned, in an initial range, corrosion resistance increased but after this initial range, no considerable change in resistance observed. For operational temperature, it was observed again that in a certain range of temperature the coating had its best resistance and out of that this resistance decreased. For accelerators concentration, in its low concentrations the corrosion resistance was more comparing to its high concentrations. And as far as the activators concentration was concerned, in lower concentrations the coating had higher corrosion resistance than in higher ones.

Stroke after, heart disease and cancer, is the third most common cause of death. Intracranial hemorrhage is the third most frequent cause of stroke. Primary (hypertensive) intracerebral hemorrhage that is due to predominantly to chronic hypertension and degenerative changes in cerebral arteries and gastrointestinal bleeding is one of its acute phase complications. The purpose of this cross sectional analytic study was to find correlation between gastric Acidity and location of intracerebral hemorrhages and blood pressure of patients.Methods and Material: This study was performed on 89 patients with primary intracerebral hemorrhage that referred to Ahvaz Golestan hospital between1381-1382. The location of hemorrhage was detected by brain CT scan at the first day of admission to hospital. Acidity of patients’ gastric juices was measured four times (2 times in first day and 2 times in fourth day) and simultaneously patients' blood pressure was determined.Results: According to this study there was a significant correlation (P< 0.05) between gastric Acidity and intrathalamic hemorrhage in the first day. So that, patient with intrathalamic hemorrhage had higher gastric Acidity than others. Patients' mean blood pressure did not have a significant correlation with gastric Acidity and location of intracerebral hemorrhage.Conclusion: Regarding the position of thalamus that is near hypothalamus and its role in secretion of gastric acid, one can guess a high gastric Acidity in first day due to stimulating effect of intrathalamic hemorrhage; furthermore, prescription of antacid agents in the first day after intrathalamic hemorrhage can prevent gastric bleeding.

In order to investigate the influence of processing variables such as particle drying temperature, press temperature and hardner consumption on wood Acidity and bonding performance of UF resin, experimental boards were produced using beech wood particle, drying temperature varied at 80, 110 and 140°C, press temperature at 150, 165 and 180°C and hardner consumption at 1, 1.5 and 2% (based on solid content of UP resin). Eighty one sample boards were produced and tested. The results of physical and mechanical properties measurements were as follows: Modulus of rupture and modulus of elasticity of boards produced with particles dried at 80°C were higher than 110 and 140°C. Application of 2% hardener with increasing press temperature decreased MOR and MOE. Internal bonding of boards were measured and the results indicated that drying temperature had significantly effected the IB and boards produced  with particles dried at 80 and 140°C, produced highest IE and lowest IE was belong to 110°C. The effect of hardner consumption was statistically significant and the highest IB was belonging to 2% hardner consumption. The results of thickness swelling measurement after 2 hr. soaking in water indicated that T.S2 of boards produced with particles dried at 140°C were the lowest. The combined effect of press temperature and hardner consumption on T.S2 was statistically significant and at 2% hardner consumption with increasing press temperature, increased thickness swelling.

A survey of the literature shows that the source of total Acidity in crude oils is due to naphthenic acids available in their hydrocarbon matrices. On the contrary, our studies show that the emulsion water in crude oil is responsible for the main part of total acid number (TAN), especially for heavy crude oils. In order to avoid metal corrosion in refining facilities and transport lines of crude oil, a special care is needed to control the Acidity level of heavy crude oils. In the current work, a new technique based on chemical treatment and centrifugal separation was developed in order to decrease the total acid number of off-spec heavy crude oils. This method was ideally suited for the acid removal of heavy crude oils including water and salt at the level of 0.05-20 vol% and 10-10000 ptb respectively.