Determination of the Diffusion Coefficient on the base of solution of a linear inverse problem of the parameter estimation using the Least-square method is presented in this research. For this propose a set of temperature measurements at a single sensor location inside the heat conducting body was considered. The corresponding direct problem was then solved by the application of the heat fundamental solution.

In this paper, the molecular Diffusion Coefficient is calculated by obtaining experimental data of gas Diffusion in stagnant solvent and using mathematical models based on Fick's second law. The purpose of this paper is to calculate the ethylene Diffusion Coefficients in n-methyl pyrrolidone (NMP) solvent at initial pressures of 600, 800 and 1100 kPa and temperatures of 278. 1, 298. 1 and 328. 1 K using two available models. Although similar to previous researches, the experimental results from both models showed that the Diffusion Coefficients increase with increasing temperature, the type of dependence on temperature as DAB = A. Tn has been different from the researchers' point of view. To examine, the experimental results were compared with the predictions of Wilke-Chang model, in which n = 5. 65, and Diaz model, in which n =8. 5. The dependence of the molecular Diffusion Coefficient on temperature in the two experimental models is different, and the prediction of the Diaz model had better agreement to the experimental data of this study.

To know about Diffusion and moisture surface emission Coefficients of timber is a proper criterion for simulation and estimation of the required time for timber drying. There are various factors such as moisture percentage, timber temperature, adjacent air speed and surface conditions which may influence one or both Coefficients. In the present survery, according to drying curves of 2.5 and 3.2 cm thick Querus castanefolia lumbers, dried in a conventional kiln under T4-D3 schedule, Diffusion and surface emission Coefficients were calculated. In the range of 10-40 percent moisture content, it was indicated that the results of using two drying curves simultaneously were in agree with the results of using a single drying curve for each thickness. While, in the same moisture content range, the average drying rate of the 2.5 cm lumbers was significantly higher than that of the 3.2 cm samples.

Background: Diffusion-weighted imaging (DWI) is a form of magnetic resonance imaging (MRI) based on measuring the random Brownian motion of water molecules within the biological tissues and is particularly useful in tumor characterization.Objectives: The purpose of this study was to evaluate the diagnostic value of DW MRI and the apparent Diffusion Coefficient (ADC) for preoperative grading of astrocytic supratentorial brain tumors.Patients and Methods: Twenty-three patients (14 females, 9 males, mean age 43 years) with astrocytic supratentorial brain tumors underwent preoperative conventional MR imaging and DWMRI. The minimum, maximum and mean ADC values and them inimum, maximum and mean DWI signal intensities of each tumor were taken by placing several regions of interest in the tumor on DWI images and ADC maps. To assess the relationship between these values and the tumor grade, we used the Mann-Whitney U test and the Spearman correlation. Receiver operating characteristic (ROC) analysis was used to determine the cutoff value of the minimum, maximum and mean ADC values and the minimum, maximum and mean DWI signal intensities that had the best composition of sensitivity and specificity for differentiating low-grade and high-grade astrocytic brain tumors.Results: According to the pathology reports, 10 patients had low-grade astrocytomas (grades I, II) and 13 patients had high-grade astrocytomas (grades III, IV). The minimum ADC value showed a significantly inverse correlation with astrocytic tumor grade (P= 0.006). The correlation between the maximum ADC value and the maximum DWI signal intensity with tumor grade was direct (P= 0.013, P=0.035). According to the ROC analysis, the cutoff values of 0.843×10-3mm2/s, 2.117×10-3mm2/s and 165.2 for the minimum ADC, maximum ADC and maximum DWI respectively, obtained the best combination of sensitivity and specificity for distinguishing low-grade and high-grade astrocytomas.Conclusion: Measuring minimum ADC, maximum ADC and maximum DWI signal intensity can provide valuable information for grading of astrocytic supratentorial brain tumors before surgery.

The deterioration of concrete structures is a non-linear and complex phenomenon which is caused by different phenomena. Carbonation is known as one of the major reasons of concrete deterioration. Carbonation has two different effects on concrete structures. Carbonation may have a positive effect against corrosive materials because of its effect in reducing the concrete porosity by changing calcium hydroxide to calcium carbonate. On the other hand, carbonation may have a major role in improving corrosion by reducing the pH of concrete and omitting of passive layer. Although literatures on carbonation have been vast, there are so few studies in carbonation of concrete containing silica fume. In this research the effect of carbonation in reducing of the porosity of concretes containing silica fume was studied. For this reason, concrete specimens with different water to binder ratios (w/c = 0, 0. 35 and 0. 5) and silica fume percentage (S. F = 0%, 5% and 10%) were made and carbonated in different ages (28 and 90 days). The porosity of carbonated concretes compared with control specimens by different experiments. Finally, a mathematical model for concrete porosity reduction under carbonation phenomena was developed based on experimental results.

Background: In the magnetic resonance imaging (MRI) of many tissues, apparent Diffusion Coefficient (ADC) values vary with age. In the literature, there are no studies in which normal cervix ADC values and their relationship with age is analyzed. Objectives: To evaluate whether changes occur in ADC values with aging in the uterine cervix with 3-Tesla MRI. Patients and Methods: Female patients aged between 18 and 70 years who were found to have lower abdominal Diffusion-weighted magnetic resonance imaging (DWI) in the radiology database from December 2017 to May 2018 were evaluated. All DWI examinations were performed using a 3-T MR with 2 b values (b = 50, 800 s/mm ). A total of 161 patients were divided into two groups according to their menopausal status (premenopausal n = 106, postmenopausal n = 55). To evaluate the correlation between the age of the patient and the ADC values, Pearson correlation analysis was performed. Results: The mean age of the patients was 41. 4-11. 6 years. The mean ADC value was 1. 276-0. 25 mm 2 in the whole population. There was a negative correlation between age and ADC values. The mean cervix ADC value of premenopausal and postmenopausal patients was 1. 333-0. 23 mm2-3 /sec 10 2 and 1. 165-0. 25 mm/sec 10-3, respectively. There was a statistically significant difference between the groups in term of cervix ADC value (P < 0. 05). Conclusion: A negative correlation between aging and ADC values was found. Menopausal status has an effect on the ADC values of the cervix. These findings may indicate cellular and extracellular matrix changes in the cervix tissue with aging and menopausal status.

Rhabdomyosarcoma is a common primary childhood malignancy that rarely metastasizes to the breast. We report a patient with a primary sinonasal rhabdomyosarcoma metastasizing to the breast, with no distant spread. We describe the imaging appearance of rhabdomyosarcoma on magnetic resonance imaging (MRI), particularly on Diffusion-weighted imaging (DWI) and apparent Diffusion Coefficient (ADC) sequences. Rhabdomyosarcoma metastasis has a variable appearance on ultrasound and MRI, and may mimic common benign tumors. However, it appears hyperintense on DWI and produces a low value on the ADC, which may be more accurate for determining its malignant nature.