فهرست مطالب سید محمدجواد حسینی

With the increase in the number of infections and deaths of covid-19, the need is felt to use artificial intelligence and machine learning tools to diagnose the corona virus quickly and on time. In this study, using chest x-ray images and VGG-16 deep neural network, an automatic system was designed and implemented to detect cases of covid-19.

In this research, chest x-ray images obtained from the Kaggle database were used. The design of this study included: data sampling, training division, creating directories, transferring images to their own folders, classifying images, creating the proposed VGG-16 model in Python programming language and Keras and Tensorflow libraries, evaluation of the proposed model and finally the creation of the confusion matrix and their analysis and interpretation.

The accuracy and Precision of the proposed model for the positive Covid-19 class were 91 and 93%, respectively. Also, the recall rate and F1-Score for cases with covid-19 were 94% and 88% respectively.

Due to the high accuracy and precision of the proposed model, it can be used to diagnose covid-19 and separate COVID-19 cases from healthy cases and also be used as an auxiliary tool to help doctors diagnose this disease.

In this article, the Jennings method has been improved by using the third-order spline interpolation function. In this research, in order to be able to compare the advantages and disadvantages of the Jennings method, which is based on exact relationships and the assumption of linear changes of the excitation, compared to the spline interpolation method, a damped one-degree-of-freedom linear system under sinusoidal harmonic loading is considered has been taken. Exact values of the deformation response coefficient of this system are available for different excitation frequencies. The approximate values of the deformation response coefficient of this system for different excitation frequencies were calculated assuming linear interpolation of excitation and also assuming interpolation with spline function and were compared with their exact corresponding values. This work was done for two, five, ten and twenty percent damping. The results of the work indicated that when the number of points by which the sine wave is approximated is small and also the amount of damping is low, the interpolation with the spline function has a significantly higher accuracy than the linear interpolation mode. Another noteworthy point is the high sensitivity of the cubic spline interpolation to the level of system damping, so that for a certain number of divisions, the error value is highly sensitive to the damping value. Thus, with the increase of damping, the sign of the error changes and its value increases strongly for the number of large divisions.  This phenomenon is not seen at all in linear interpolation.Therefore, considering that in interpolation using the spline method, the continuity of the slope and the second derivative are maintained in the internal points, it is suggested to use this method to calculate the dynamic response of linear systems and the results obtained with the results of Jennings' method should be compared and appropriate decisions should be made if there is a significant difference in the analysis results obtained from these two methods.It is important to mention that the execution time of the computer program related to the cubic spline interpolation method is longer than the Jennings method. Because in the spline interpolation method, it is necessary to solve the system of linear equations with the number of unknowns equal to four times the number of intervals, while in the excitation linear interpolation method, it is not necessary to solve the system of equations at all and simply by having the velocity and displacement at the beginning of the step and assuming that the excitation is linear during the desired time step, the coefficients A, B, C, D, A', B', C', D' were calculated and using this eight coefficient, velocity and displacement at the end of the time step are obtained. It should be noted that if the time interval between different accelerogram points is constant, it is sufficient that the coefficients A, B, C, D, A', B', C', D' are calculated only once.

Domestic refrigerators have become an essential part of modern life.Since these devices are connected to the power grid and operate continuously throughout the day and year, they consume a lot of energy.Experimental studies show that adding phase change materials in refrigerators in different places improves the energy efficiency of these appliances.In this study, the effect of adding a phase change material(PCM)box on the thermal performance and electricity consumption of a single-door refrigerator/freezer is studied.The box of phase change material is attached to the bottom surface of the evaporator with different materials.Water with a melting temperature of zero degrees Celsius has been used as a phase change material.To study the effect of increasing the thermal conductivity of water, fins with the same material(copper, aluminum and steel)as PCM box are placed in the box to evaluate their effect on temperature distribution and power consumption.The results show that the presence of the water box in contact with the bottom surface of the evaporator helps to reduce the temperature of the cabin due to the potential of water as a phase change material in absorbing and releasing cooling energy.Also, the results show that copper is more suitable for water storage because of its higher thermal conductivity and it helps to more evenly distribute the temperature.Furthermore, using a fin inside the water chamber, in addition to limiting the temperature range of the cabin, on average causes a further reduction in energy consumption by 1 to 4% compared to the case without a fin.

During the Coronavirus disease 2019 (COVID-19) pandemic, children are less affected than adults, and underlying conditions and older age are associated with severe disease. Following the SARS-CoV-2 pandemic, outbreaks of cases with Kawasaki-like disease and a few others with the multisystem inflammatory syndrome in children related to COVID-19 (MIS-C) have been reported. Here, we report a two-year-old girl initially admitted to urgent pediatric care and was diagnosed with Kawasaki disease associated with COVID-19 infection to highlight the clinical features and signs. Physical examination showed a fussy infant with swelling of the hands, feet, and lips, red lips, restlessness, anorexia, and fever. According to the clinical and laboratory findings, Kawasaki disease was diagnosed. Laboratory tests for SARS-CoV-2 were positive. The patient's clinical symptoms improved after receiving medications such as IVIG and ascorbic acetyl acid.

The purpose of the present study is to review the relationship between religiosity/religious attitude and tendency to cheating in exams among university students. This research is descriptive-correlational and its statistical population involves all the students (around 5000) at the faculty of humanities at Islamic Āzād University of Qom in 2019. Using Morgan table, 360 students were chosen by stratified random sampling and they answered to 3 Questionnaires including religious attitude designed by Barāheni, religiosity designed by Glock & Stark, and tendency to cheating designed by Savāri (2012). The results showed that there is a positive and significant relationship between religiosity/religious attitude and tendency to cheating in exams. Moreover, there is a negative relationship between subcategories of religiosity and tendency to cheating. The results of regression analysis showed that both variables of religiosity and religious attitude have the potential to predict the tendency to cheating and just the consequential aspect of religiosity among all its aspects could negatively prediction in this regard. The results of the test showed that there is a significant difference between boys and girls in terms of their tendency to cheat and that girls have a higher average. According to the results, it is suggested that by providing education in line with fostering religious beliefs and awareness and religious attitude among university students, we pave the way to decrease cheating in educational fields.

This research is mainly focused on to study microstructure and mechanical properties of AA5051 aluminum alloy deformed by equal-channel angular pressing (ECAP) process at 200˚C and in BC routes and 4 four passes. The ECAP processing was carried out using die with an intersecting channel angle ‘ϕ’= 120° and corner angle ‘Ψ’= 20°. The results of uniaxial tensile test showed that tensile strength was found to be increased from 115MPa for annealed sample to 239MPa after four passes ECAP in route BC that shows that the strength in ECAP samples has increased. In addition, the percentage of elongation also decreased in initially passes and then increased slowly. Microstructure and grain refinement of specimens were investigated by optical microscopy and scanning electron microscopy and fractography were investigated by scanning electron microscopy. The grain size of annealed sample was 123μm and decreased to 18μm after four passes ECAP in route BC. The hardness also increased from 51HV in annealed sample to 90HV the fourth passes.

Pseudomonas aeruginosa is one of the most important pathogens commonly seen in immuno-compromised patients. Septicemia due to this organism is rare in healthy individuals. We reported a multiple trauma patient with septicemia due to Pseudomonas aeruginosa and Acinetobacter.

The case was a male patient of 43 years old who had experienced multiple trauma. Before referring to Baqiyatallah hospital, the patient had been admitted to another hospital for treatment. The case was studied by clinical and paraclinical examinations.

The patient was febrile and toxic. His traumatic lesions were purulent. He was introduced to surgery unit for debridement of traumatic lesions. Pseudomonas aeruginosa and Acinetobacter were isolated from traumatic lesions.

It seems that nosocomial infection due to Pseudomonas aeruginosa and Acinetobacter was causative agents of septicemia in the patient during the first hospitalization. Infection surveillance and control programs play a key role in prevention of nosocomial infections in hospitals.

Despite the advances in medical technology has resulted in decrease of occurrence of infectious disease, tuberculosis is still the most common cause of mortality. Prisoners are at high risk of acquiring TB. The most common reasons are overcrowding, malnutrition, high-risk behaviors, addiction and HIV infection. In current study, the epidemiology and prevalence of TB in prisons in Iran was investigated.

Checklists were obtained from prisons throughout of Iran and data were then analyzed to determine the prevalence of TB among the prisoners.

In this study, 339 patients were diagnosed with TB. All patients were older than 15 years. All except two patients were male. In 83 cases, TB infection is along with HIV.

Because of unfavorable environment of prison the level of TB in prisons is higher than that of the civilian population. Additionally high levels of MDR-TB in prisons have been reported from some studies. The results obtained from current study indicated the prevalence of TB also is high in Iranian prisons and in 83 persons it was along with HIV infection which can make difficulty in treatment and increase the risk of MDR. These results show the important role of control and treatment of TB in prisons.