Frozen sand soils are often observed in underground urban and engineering constructions in cold climates. Artificial ground freezing is a soil improvement technique, and soils in coastal areas are mostly comprised of poorly-graded sand with low moisture and temperature. Thus, it is required to explore the effects of different factors on the strength of frozen soils in such areas. In addition, the freezing age required to obtain sufficient strength is studied. The present study investigates sand from the Shorabil Lake shore in Ardabil, Iran, frozen in cold seasons. To evaluate the effects of the soil grain size, sands with gran sizes of 0.15 and 0.25 mm mixed with clay in different ratios were employed. Uniaxial compressive Testing was implemented to measure the unconfined compressive strength of ten soil mixtures with four moisture contents. Thus, a total of 40 mixtures were studied at three freezing ages. The stress-strain curves showed strain softening. The specimens had almost the same strength at shorter freezing ages. As the freezing age increased, different stresses were observed due to the clay content; the strength of a specimen with a low clay content remained almost unchanged as the freezing age increased. The specimen with a clay content of 50% and a moisture content of 15% had a strength of 205.5 kPa at a freezing age of 24 h and 283.8 kPa at a freezing age of 72 h. Also, the specimen with a clay content of 10% and a moisture of 15% was found to have strengths of 265.4 and 283.8 kPa at the freezing ages of 24 and 72 h, respectively. Several specimens underwent an up to 36% decline in strength as the sand grain size decreased; however, the trend was still the case, and the specimen with 30% clay showed the highest strength in most cases.

Background: There are many methods for evaluating a traumatized metacarp. Objectives: This study sought to evaluate the accuracy of the metacarpal Compression Test for the diagnosis of metacarpal fracture. Methods: All patients with metacarpal trauma were Tested via placement of axial load (Compression) on the metacarpal; induction or exacerbation of pain on each metacarp was recorded upon applying axial pressure. Then, an X-Ray imaging system was used to identify and record the presence of fracture. All data were entered into a 2x2 table, and then negative predictive value (NPV), positive predictive value (PPV), sensitivity and specificity of the Test were calculated. Results: After careful physical examination and application of the axial pressure on the metacarpal bone, 16(23. 68%) patients did not experience any pain during axial loading (none had fracture). According to the statistical analyses of the data, the proposed method had a 69% specificity, 100% sensitivity, 86% PPV and 100% NPV. Conclusion: Our findings showed that axial loading applied on the metacarpal bone, when it leads to pain, is a good marker for fracture. On the other hand, patients with negative Test results had no fracture on radiography, which emphasized 100% NPV of the Test.

The study of the physical properties (geophysical methods) of rocks associated with its mechanical properties has recently received lots of attention. Recent studies show that geophysical methods especially the seismic and geoelectric methods are able to estimate the mechanical parameters and recognize their spatial variations, including anisotropy. Meanwhile, electrical and seismic methods are the most used one.Electrical measurement is one of the non-invasive geophysical methods commonly used by engineers working in various fields such as mining, geotechnical, civil, underground engineering as well as oil and gas mineral explorations. This method can be applied both in laboratory and in the field. Numerous scientists have focused on the relation between resistivity and porosity. However, there is a very limited study on the relation between the electrical resistivity and the rock properties apart from porosity.In this paper, changes in the electrical conductivity of rocks during a uniaxial Compression Test were investigated in laboratory. The uniaxial compressive strength, elastic modulus, and density values of the samples were determined in laboratory. We installed special electrodes on seven nearly saturated core samples in order to measure the resistivity. Core samples had a 52-mm diameter and a 110-mm length. Two-electrode as well as four-electrode arrays were both used in resistivity monitoring in laboratory. Using a four-electrode array minimized the undesirable electrode polarization effects. In the four-electrode array, we used two non-polarizing Ag/AgCl electrodes mounted on the core sample. Our laboratory observations showed that there was not any electrode polarization effect. When we used a two-electrode array, the resistivity changes were less than 5 percent compared to a four-electrode array. In our laboratory investigation, we used different sedimentary core samples including sandstone, fossilioferous limestone and travertine. Maximum resistivity observed for the travertine core sample was less than 12 kohm. During the uniaxial compressive Test, deformation measurements were made and the stress–strain curves were plotted. Tangent Young’s modulus values were obtained from stress–strain curves at a stress level equal to 50% of the ultimate uniaxial compressive strength.Sandstone core samples showed a resistivity increase in the whole strain range. On the contrary, the fossiliferous limestone samples (thin section showed that the sample was composed of tiny calcium fossils in a fine aggregate of micrite cementation) showed a resistivity decrease in the whole strain range. Travertine and limestone showed an intermediate behavior (resistivity increased in the lower strain and it decreased in the higher range). In other words, the onset of new crack formation occurs well inside the quasi-linear part of the stress-strain curve. The quasi-linear portion of the stress-strain curve was the result of a competition between closure of one population of cracks, and the growth of new propagation of the existing cracks.Resistivity behavior during a uniaxial Compression load is closely related to the pores in the lower strain ranges and then to the new induced fractures in higher strains. Our results showed that the electrical resistivity may be a representative measure of the rock properties. Additionally, the effect of certain minerals on the rock’s resistivity must be taken into account. The results indicated that the rock structure had an important effect on the resistivity behavior during a mechanical loading.

Background: Chronic diabetes is substantially associated with circulatory disorders in lower limbs. Vacuum-Compression Therapy (VCT) has been commonly used in treatment of peripheral circulatory disorders. VCT is based on intermittent alteration of Positive- Negative pressure phases. The purpose of this study was to determine effects of VCT on diabetic subjects' peripheral blood flow.Methods: In this Before-After and case-series study, 18 type 2 diabetic subjects with diabetic neuropathy and/or peripheral vascular disease (PVD) completed the study. Subjects received 45 min of VCT for 10 sessions three times weekly. Blood flow (calf+foot) was measured via venous occlusion plethysmography.Results: Among Variables of "Arterial Inflow", "Venous Outflow", "Venous Capacity", "Postischemic Reactive Hyperemia" and "Peak Flow of Reactive Hyperemia", only "Venous Outflow" significantly improved after 10 sessions treatment via VCT (P<0.05).Conclusions: Arterial blood inflow, which was the most important determinant evaluated in this study, was not increased via VCT. Additional studies are required to investigate the effective VCT parameters and duration of each session and number of sessions, considering progressive and deteriorative natural history of diabetes.

Physical examination is the most important procedure for examining traumatized patients and ruling out possible bone fractures. Edema, deformity, ecchymosis, tenderness on trauma location, and limited bone movement are among the signs of fracture. The diagnosis is documented by plain radiography. The number of false positive cases in this Test increase in the presence of soft tissue injury along with bone damage. In this case, a great number of X-rays will be taken daily and many patients will be exposed to radiation, unnecessarily (1). The question to be fully answered is whether all cases of trauma and pain require radiographs or not? ...

The intervertebral discs are of the most important body tissues that provides the required flexibility for the spine during daily activities. Due to the lamellar structure of the Annulus Fibrosus, that surrounds the central part of Nucleus Pulposus, it may show anisotropic behavior in carrying the applied loads. Therefore, this aspect was investigated using the experimental data that were obtained by confined Compression relaxation Tests on samples in three different directions: Axial, radial and circumferential. To obtain the experimental values of the permeability and aggregate modulus as material parameters, Test data in three directions were fit to the constitutive equations that were based on the biphasic relaxation model. The results for the permeability and aggregate modulus in three directions show that the material parameters are almost independent of direction and therefore, it is concluded that AF can be treated as an isotropic material under the compressive loads.

In this research, the hot deformation behavior of W360 tool steel was investigated using hot Compression Test at 10001200°, C and strain rates of 0. 001, 0. 01, 0. 1, and 1 s-1. According to the results, dynamic recrystallization was found the most important restoration factor of this alloy during hot deformation. Recrystallization was enhanced with an increase in temperature and strain rate. Also, the hot working process was optimized by drawing the processing map of this steel. Microstructural images obtained from the hot Compression Test showed that recrystallization started at 1000°, C and the strain rate of 0. 01 s-1 and developed with increasing temperature and strain rate due to an increase in the stored energy and suitable regions for nucleation. The results of drawing the processing map showed that the best hot deformation region was the temperature range of 1050-1150°, C and strain rates of 0. 1-1 s-1.

To define failure under biaxial stress, a three-dimensional surface in terms of two principal stresses and their orientation to the bed joints is required. This article describes a series of biaxial Compression Tests on full-scale brick specimens. Tests were performed on square unreinforced grouted brick masonry specimens with the principal compressive stresses oriented at 0 and 90 degree angles to the bed joints, and a failure surface was obtained in terms of these parameters. Test results indicated that the masonry strength under equal biaxial Compression is higher by about 36% on average than that under uniaxial Compression; the influence of joint orientation is very in significant and negligible for these models.