ABSTRACT
Kinetic hydrate inhibitor laboratory testing before field application is one of the key priorities in the oil and gas industry. The common induction-time-based technique is often used to evaluate and screen for kinetic hydrate inhibitors (KHIs). However, the main challenge relates to the stochastic nature of hydrate nucleation observed in fresh systems, which often results in scattered data on hydrate formation with unacceptable uncertainties. A much more precise KHI evaluation method, called crystal growth inhibition (CGI), provides comprehensive insights into the inhibitory behavior of a kinetic hydrate inhibitor, including both hydrate formation and decomposition. Given that industry does not require this much information, it is not feasible to expend either much time or cash on this strategy. This study aims to provide a cost-effective technique that presents maximum data accuracy and precision with relatively little time and cost expenditure. Hence, the impact of water-hydrate memory on improving the accuracy and repeatability of the results of the induction-time-based technique (IT method) was examined. First, the concept of water-hydrate memory, which contains information about how it is created, was reviewed, and then, the factors influencing it were identified and experimentally investigated, like the heating rate of hydrate dissociation and the water-hydrate memory target temperature during heating. Finally, a procedure was developed based on the background information in the earlier sections to compare the consistency of the results, originating from the conjunction of water-hydrate memory with the IT technique. The results of replications at KHI evaluation target temperatures of 12.3-12.4°C and 11.5-11.7°C showed that more repeatable data were obtained by applying water-hydrate memory, and a more conclusive decision was made in evaluating KHI performance than with an IT method. It seems that combining the IT method with water-hydrate memory, introduced as the "HME method", can lead to more definitive evaluations of KHIs. This approach is expected to gain in popularity, even surpassing the accurate but complex and time-consuming CGI method.
ABSTRACT
We presently report the case of COVID-19 in a 38-year-old male who had come to the primary health care clinic of Shahid Beheshti University of Medical Sciences, which specializes in the COVID-19 epidemic. He reported having fatigue, myalgia, fever, rash, and loss of taste and smell. The physical findings were maculopapular rash over his trunk, inguinal regions, and left arm, erythema of larynx with an aphthous lesion on left tonsil, he did not have a fever, and respiratory distress symptoms. There were no changes regarding COVID-19 in the spiral lung CT scan. However, the result of PCR for COVID-19 RNA was positive.
ABSTRACT
Objective: The goal of this research was to investigate the efficacy of perioperative manual acupuncture in the LV 3 and LI 4 points for lessening hemodynamic changes during endotracheal intubation in patients who were receiving anesthesia. Materials and Methods: This double-blinded randomized controlled study enrolled patients who were undergoing endotracheal intubation, in 2015-2016, during general anesthesia in the general surgery department of the Imam Khomeini Hospital complex, in the Tehran University of Medical Sciences, Iran. The patients were randomly allocated into 2 groups with 30 patients in each group. In the treatment group, acupuncture needles were placed at LV 3 and LI 4, whereas, in the control group, the needles were placed 1 cm lateral to these points. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP), and heart rate (HR) before and after placing the acupuncture needles, after induction, immediately, 1 minute, and 3 minutes after intubation were measured and recorded prospectively. Results: The patients had a mean age of 44.45 ± 12.72 years and included 35 (58.3%) males. Before acupuncture, demographic data, mean blood pressure (BP), and mean HR of the patients were not significantly different in the treatment and control groups. The mean SBP, DBP, MAP, and HR of all patients changed over time significantly (P < 0.001 for all). In the treatment group, mean SBP, DBP, and MAP changes immediately after the needles were placed were significantly less than those in the control group (P = 0.033, 0.024, and 0.024, respectively). Conclusions: Although acupuncture could have a very-short-term effect that reduces BP during endotracheal intubation, hemodynamic changes might not be prevented during endotracheal intubation.
ABSTRACT
In this study, a new approach for the auto-design of neural networks, based on a genetic algorithm (GA), has been used to predict collection efficiency in venturi scrubbers. The experimental input data, including particle diameter, throat gas velocity, liquid to gas flow rate ratio, throat hydraulic diameter, pressure drop across the venturi scrubber and collection efficiency as an output, have been used to create a GA-artificial neural network (ANN) model. The testing results from the model are in good agreement with the experimental data. Comparison of the results of the GA optimized ANN model with the results from the trial-and-error calibrated ANN model indicates that the GA-ANN model is more efficient. Finally, the effects of operating parameters such as liquid to gas flow rate ratio, throat gas velocity, and particle diameter on collection efficiency were determined.
