Gas hydrate often occurs in natural gas pipelines and Process equipment at high pressure and low temperature. Methanol as a hydrate inhibitor injects to the potential hydrate systems and then recovers from the gas phase and re-injects to the system. Since methanol loss imposes an extra cost on the gas Processing plants, designing a Process for its reduction is necessary. In this study, an accurate back propagation neural network (BPNN) is designed for the prediction of methanol loss by the gas phase as a function of temperature, pressure, and methanol composition in the aqueous phase. Different configurations of BPNN were trained, tested, and a configuration providing the smallest absolute average relative deviation (AARD%) was chosen as an optimum structure. Finally, comparisons made among the accuracy of the developed BPNN model, Process Simulators, and probabilistic neural network (PNN). Results confirm that the designed BPNN model is more accurate than the other considered predictive tools. The BPNN provided an AARD=5. 75% for prediction of experimental data, while Aspen-HYSYS, Aspen-Plus, and PNN presented an AARD% of 9. 71, 12. 57, and 13. 27, respectively.

In recent years, the global market for natural pigments has grown greatly due to the increase in people's awareness of health, and environmental issues and the discovery of the medicinal effects of different natural pigments. The industrial production of natural microbial pigments has received more attention than other sources due to several advantages, such as cheaper production, easier extraction, higher efficiency, and a lack of dependence on the seasons. Among the most important natural pigments are carotenoids, flavonoids, tetrapyrroles, and some xanthophylls, such as astaxanthin. Among the carotenoids, beta-carotene, a pigment that is mostly Used in industries, is obtained from some microalgae and cyanobacteria. Astaxanthin is a red pigment with great commercial value in animal feed, pharmaceutical, and aquaculture industries. This study introduced some Commonly Used pigments produced by microorganisms along with their application and some identified microorganisms that can produce these pigments.

Background and Aim: Bacterial contamination of dental materials and devices Used in dental clinics and laboratories can lead to infectious diseases in patients, dentists and dental care providers. The aim of this study was to examine bacterial contamination of four dental materials.Materials and Methods: In this analytic-descriptive study, flour of pumice, zinc oxide powder, prophylaxis paste and wooden wedges of available commercial brands were tested. To assure an examiner-blind study, the samples were coded in the microbiology laboratory. In sterile conditions, the samples were inoculated in tryptycase soy broth and sodium tioglycolate for aerobic and anaerobic bacterial growth, respectively. The media was then incubated in 35 degrees centigrade and checked daily.Results: Flour of pumice showed contamination to coagulate-negative staphylococci, enterococcus faecallis, bacillus and diphteroid. Some of the prophylaxis pastes were contaminated with micrococcus roseous, coagulate-negative staphylococci and diphteroid. One brand of wooden wedges demonstrated contamination to staphylococcus, diphteroid and bacilli. Zinc oxide powders were not contaminated. None of the samples showed contamination to anaerobic bacteria.Conclusion: Some of the investigated materials showed bacterial contamination, but the identified bacteria are not pathogen in normal situations.

Introduction: Different models of tractors have been imported from foreign countries or assembled in Iran for many years. Consistency of foreign manufactured products with native specifications and the improvement of locally manufactured tractors are important problems that must be considered. Moreover, tractor dimensions, sitting space and some other important factors such as the ability of Iranian users to operate them must be taken into consideration. In this study, we surveyed the proper proportion of tractors dimension, location of control tools and driver’s work space, with Iranian users’ anthropometric data of drivers from five provinces. Human factors are of paramount importance in developing farm machinery given that these machines will often be operated by persons with minimum skills. ...

Background: Pressurized metered dose inhalers (pMDIs) are Commonly Used in patients with asthma. However, the need to coordinate inhalation with inhaler actuation means that they are not suitable for use per se. Spacer devices were developed to overcome some of the problems of pMDIs. Several types of holding chambers of different sizes are available in Iran. This study was designed to compare spirometric parameters between Asmyar® and Damyar® spacers in asthmatic patients. Materials and Methods: This was an observational comparative study. Patients with mild to moderate asthma were entered in this study. The ease of use, convenience, and portability of the mentioned spacers were evaluated using a visual analogue scale (VAS). Lung function was assessed by using a portable spirometer (Spirolab® Italy) and spirometric parameters of FEF50%, FEF25-75%, PEF, FEV1, FVC and FEV1/FVC were measured.Results: Forty patients (25 females, 15 males) with a mean age of 43.10±12.99 years were studied. Mean ± SD changes of FVC, FEV1, PEF, FEF25-75%, FEF50% and FEV1/FVC (as percentage of the predicted values) before and after using Asmyar® were not significantly different from those of Damyar®. However, patient satisfaction was significantly higher with Damyar® (P<0.0001).Conclusion: Lung response after using salbutamol with either Damyar® or Asmyar® spacers was not significantly different.