[en] Highlights: • A new unsteady jet using semi-sinusoid signal is applied to form a flow control method. • The new unsteady jet overcomes the drawbacks of the traditional synthetic jet and increases the efficiency of the drag reduction. • The influence of the control frequency on control efficiency is taken into considerations. • The mechanism of the drag reduction through deviating and stabilizing the shear layers by the unsteady jet is found and interpreted. -- Abstract: A numerical simulation based on the Large eddy simulation method is carried out on the near wake flow behind a 25° slant angle Ahmed body to analyze and establish a new method to control the near wake flow. An active flow control using a new unsteady jet derived from the traditional synthetic jet is applied to reduce the aerodynamic drag. The control devices are distributed along the separation edges on the rear part of the body. Their effects on the near wake and the rear body by influencing the flow topology and the static pressure distribution are examined respectively. The control frequency of the jet as the key forcing parameter is taken into consideration as well. The different actuation set-ups lead to a max drag reduction of up to 13.6%, which demonstrates a good correlation with the static pressure distribution at the rear end of the body.

[en] Extramedullary plasmacytoma (EMP) is an uncommon tumor arising from clonal proliferation of atypical plasma cells, and it commonly develops outside the bone. Although EMP frequently affects the head and neck areas, any extraosseous organ may also be involved. Adrenal involvement is a rare finding. To the best of our knowledge, only three cases of EMP in the unilateral adrenal gland have been currently reported in the literature. We report here on a rare case of EMP that involved the bilateral adrenal glands on the MR images. In conclusion, we report here on the first documented case of extramedullary plasmacytoma involving the bilateral adrenal glands. Although the morphological appearance of EMP on MRI is nonspecific and the preoperative diagnosis may be difficult, MRI or CT scanning is often needed to obtain more information before making an appropriate therapeutic decision

[en] Chronic infection of a seminal vesicle cyst is an extremely rare disorder worldwide. To date, only two cases, which were diagnosed initially by the use of contrast- enhanced CT or non-enhanced MR imaging, have been reported in the literature. We report here a case of a 78-year-old man with chronic infection of a seminal vesicle cyst to illustrate the usefulness of the pelvic contrast-enhanced MRI in making a definitive diagnosis of the rare disorder. In addition, a brief review of the relevant literature is presented

[en] Myopericytoma is a newly proposed subgroup of perivascular tumors in the World Health Organization classification of soft tissue tumors. In this study, we report a case of a benign myopericytoma with detailed multidetector CT (MDCT) findings in the parotid gland, a location that has not been described for this type of tumor previously. The clinical presentation, imaging features, histopathological and immunohistochemical findings, and the differential diagnosis with other tumors in the parotid gland are described and reviewed

[en] Primitive trigeminal artery (PTA) and primitive otic artery (POA) is a very rare entity in adult life. We present a case of PTA and POA associated with a giant unruptured cavernous aneurysm in a 54-year-old woman. The PTA and the POA arose from the sac of the aneurysm directly, which greatly complicated endovascular therapy management

[en] The aim of the present study is to determine imaging criteria for differentiating tuberculosis from primary tumors in the adrenal gland on contrast-enhanced CT. Non-contrast and contrast-enhanced CT features in 108 patients with adrenal tuberculosis (n=34) and primary tumor (n=74) were retrospectively assessed for the location, size, calcification and enhancement patterns. The primary tumors included 41 adenomas, 11 pheochromocytomas, 4 carcinomas, 3 lymphomas, 6 myelolipomas, 6 ganglioneuromas, 2 neurilemmomas and 1 ganglioneuroblastoma. Biochemical investigation was performed for all patients. Of the tuberculosis cases, 31 (91%) invaded with bilateral involvement, while 7 (9%) of the primary tumors invaded with bilateral involvement (P<0.001). Tuberculosis often showed calcification (20 of 34; 59%), whereas primary tumors infrequently showed calcification (6 of 74; 8%; P<0.001). Low attenuation in the center with peripheral rim enhancement was more commonly seen in tuberculosis (16 of 34; 47%) than in primary tumors (7 of 74; 9%; P<0.001). In the determination of tuberculosis, the highest sensitivity (91%) and accuracy (91%) were obtained with bilateral involvement, and the highest specificity (99%) was obtained with the contour preserved. In the determination of primary tumors using a combination of having unilateral involvement and being mass-like, the outcome was a sensitivity of 91%, specificity of 94% and accuracy of 92%. CT findings can differentiate tuberculosis from a primary tumor of the adrenal glands with high sensitivity and an acceptable specificity when combined with the endocrinological examination. (orig.)

[en] There is significant anisotropic dilatation during bainitic transformation from plastically deformed austenite in a structurally and chemically homogenous alloy with no externally applied stress. The abnormal dilatation was found to be due to pronounced variant selection in a specific-textured austenite based on electron backscatter diffraction analysis and X-ray diffraction. A general rule of variant selection has been proposed, that the favored variants within an austenite grain usually belong to the same Bain group.

[en] To provide a road map of pulmonary vein (PV) and left atrial (LA) variants in patients with atrial fibrillation (AF) before catheter ablation procedure using cardiac CT. Cardiac CT was performed in 1420 subjects for accurate anatomical information, including 710 patients with AF and 710 matched controls without AF. PV variants, PV ostia and spatial orientation, LA enlargement, and left atrial diverticulum (LAD) were measured, respectively. Differences between these two groups were also respectively compared. Some risk factors for the occurrence of LAD were analyzed. In total, PV variants were observed in 202 (28.5 %) patients with AF patients and 206 (29.0 %) controls without AF (p = 0.8153). The ostial sizes of all accessory veins were generally smaller than those of the typical four PVs (p = 0.0153 to 0.3958). There was a significant difference of LA enlargement between the AF and control groups (36.3 % vs. 12.5 %, p < 0.0001), while the prevalence of LAD was similar in these two groups (43.2 % vs. 41.9 %, p = 0.6293). PV variants are common. Detailed knowledge of PVs and LA variants are helpful for providing anatomical road map to determine ablation strategy. (orig.)

[en] Although tailoring stacking fault energy (SFE) through the addition of suitable alloying element can improve mechanical properties, the effect of strain must also be included to account for the Co-based alloy design. Using first-principles density-functional-theory calculations, we revealed that there is a strong effect of the strain (volumetric strain, simple strain, and volume conserving) and external pressure on the intrinsic SFE of face-centered cubic (fcc) cobalt. This result indicated a new insight into the Co-based alloys design, especially for application at high pressure and severe plastic deformation. The intrinsic SFE decreased by increasing tensile strain or decreasing pressure, thus the tendency of forming stacking faults increases which improves the mechanical properties. Effect of volumetric (hydrostatic) strain is the strongest indicated that the volume is the dominant factor in determining the SFE and the strain-induced fcc–hcp phase transformation. Different strain methods give different charge transfer between adjacent atoms and then contribute to the variation of the atomic bonding at the specific direction and SFE behavior. Application of external pressure from 0 to 15 GPa increased the elastic constants and elastic modulus of fcc Co and then improved the ductility.

[en] The diffusion mechanism of carbide-forming elements from a molten salt bath to a substrate surface was studied in this research, with particular focus on the processes occurring in the molten bath at the time of coating. Metal, oxide, and metal−oxide baths were investigated, and the coating process was performed on H13 steel substrates. Scanning electron microscopy and electron-probe microanalysis were used to study the coated samples and the quenched salt bath. The thickness of the carbide coating layer was 6.5 ± 0.5, 5.2 ± 0.5, or 5.7 ± 0.5 μm depending on whether it was deposited in a metal, oxide, or metal−oxide bath, respectively. The phase distribution of vanadium-rich regions was 63%, 57%, and 74% of the total coating deposited in metal, oxide, and metal−oxide baths, respectively. The results obtained using the metal bath indicated that undissolved suspended metal particles deposited onto the substrate surface. Then, carbon subsequently diffused to the substrate surface and reacted with the metal particles to form the carbides. In the oxide bath, oxide powders dissolved in the bath with or without binding to the oxidative structure (Na₂O) of borax; they were then reduced by aluminum and converted into metal particles. We concluded that, in the metal and oxide baths, the deposition of metal particles onto the sample surface is an important step in the formation of the coating.