Several studies of compressible flows show that the pressure-strain is the main indicator of the structural compressibility effects. Undoubtedly, this term controls the change in the Reynolds stress anisotropy. Regarding the model of Adumitroiae et al., the slow part of the pressure strain correlation like the Rotta model uses the standard coefficient C1. The model predictions do not show large differences when compressibility increases. Correction of this coefficient using the turbulent Mach number is proposed. The two forms models of Adumitroiae et al. (with and without correction of C1) are considered to study compressible mixing layers. The obtained results show that the predictions of the proposed compressibility correction model agree with the experiment results of Goebel and Dutton.

There are several geotechnical and geoenvironmental problems involve water flow through soils. The coefficient of permeability is the most important parameter that dominates the water flow pattern through soils, both in transient and steady state conditions. In the current paper the stress dependency of permeability and its effect on the ground water flow is evaluated. The results of a field instrumentation program to establish pore water pressure profile is presented and the dominant effect of stress dependent permeability characteristics of soil over ground water pressure and flow is demonstrated and compared with an analytical solution. Also, the procedure and results of a laboratory experimental work to evaluate stress dependency of permeability is elaborated. Finally, referring to the site and laboratory investigations the nature of stress dependent permeability of soil and the validity of the related equation are assessed.

Background: The most frequently used test for evaluation of fetal health is the Non Stress Test (NST). Unfortunately it has a high incidence of false positive results. The combination of vibroacoustic stimulation with the NTS has been shown to reduce non reactive results.Methods: A tests assessment method was chosen with a simple randomized sampling. 40 pregnant women with non reactive NST in the first 20 minutes who received VAS in one of Tehran University's Hospitals were compared with BPP scores. A vibroacoustic stimulation was applied for a 3 seconds on the maternal abdomen and fallowed within 10 minutes. Data collection tools were NST, sonography instruments, NST result paper, tooth brusher, watch, demographic questioner and check list. Data analysis was made by descriptive static and by using the Fisher's Exact Test (with level of significant at p<0/05). All statistical analysis were performed using an spss/win.Results: After VAS, 70% of non reactive tracing became reactive. All cases with fetal reactivity response after a VAS had a subsequent BPP score of 8 (negative predictive value of 100%). False positivity of VAS was lower than NST.Conclusion: VAS offers benefits, by decreasing the incidence of non reactive test and reducing test time. VAS lowers the rate of false positive NST. VAS is safe and allows more efficient of prenatal services. This test could be used as a rapid antepartum test to predict fetal well-being.

Purpose: Application of heavy forces to maxillary dentition during treatment with headgear, induces high concentration of stresses in periodontal tissue. Quantification of this stress is of great concern in orthodontics. This study was designed to investigate the quantity and quality of stress response in the PDL of maxillary first molar which was subjected to high pull headgear traction using Finite Element method.Methods and Material: In an experimental study, a three-dimensional finite element model of maxillary dentition, consisting of 17096 elements and 23013 nodes, was developed based on a young human skull. The forces were applied to the maxillary first molar in the stabilized Arch by means of a rectangular full size arch wire in (022) slot bracket. Mechanical properties of this model were based on previous studies. A 350 gram force was used for high pull headgear to affect the dentition (+30 degree) and stress distribution was investigated in buccal, palatal, mesial and distal side and in cervical, middle, apical sections of the PDL. The quantity of stresses were expressed as principal stresses (1,2,3), while the negative and positive signs indicated compressive and tensile stresses.Results: The buccal surface of PDL of mesiobuccal root and the buccal, palatal and distal surface in cervical region of PDL of distobuccal root and the distal surface of the PDL of palatal root had received a great deal of stresses, in addition, the over all stress distribution in roots of molar had intrusive nature.Conclusion: The extension of high stress concentration areas observed after using high pull headgear is limited to some root surfaces specially the distobuccal root.

The purpose of this study was comparing the stress of breast cancer patients to that of healthy women. A sample of 65 breast cancer patients were selected from "Imam-Khomeini Cancer Institute" (from summer to autumn of 2008). They were chosen from the available patients who were diagnosed with cancer for less than two months. Variables such as marital status, economic status, age and education were taken into consideration in both the experimental and the control groups. Pickle's "life event" questionnaire (1971) was used to assess the stress in those groups. The data were analyzed using t-test. The results suggest that the stress in breast cancer patients is significantly higher than others. Moreover, women who bereaved the loss of a relative, had unwanted pregnancy or experienced divorce had more stress.

One of the complicated phenomena in sediment hydraulic engineering is scouring around bridge pier. Regard to three-dimensional and complicated flow pattern around piers, measuring some hydraulics parameters during the tests such as flow pattern, variation of bed profile and shear stress are difficult, in this situation application of numerical models in order to extract results and more detailed study is useful. Aim of this research is numerical modeling of flow pattern, variation of bed profile and scour depth and shear stress around rectangular pier using Flow 3D and applying the results to protect piers against scouring. Results showed, for aligned pier with flow, shape of scour hole and flow pattern were symmetrical. As increase of pier angle, shear stress in front of the pier increased so that for pier with 10°,angle with flow direction, shear stress was 0. 55 N/m2. Also fluctuations of bed profile and water surface increased. Application of submerged vanes, changed scour pattern and moved sediment in front of pier which scouring was reduced. Increase of height and angle of submerged vanes improved their protective role. Base on the results of numerical model, after 30 minutes, scour depth in front of pier in aligned pier with flow and angle of submerged vanes 30°, , in same level with bed, 1. 25 cm and 2. 5 cm on the bed, was 3. 1 cm, 0. 035 cm and +0. 005 cm (on the bed), respectively. As increase of pier angle, performance of submerged vanes to control scouring in front of pier and in side of high-pressure wall decreased, but in side of low-pressure wall scouring compared with alone pier was less.