Fabrication of 1 T Bi-2223 Superconducting Magnet with 92 mm Bore Diameter at 77 K

A Bi-2223 superconducting magnet for practical use in liquid nitrogen is designed and fabricated. Bi-2223 tapesprepared by ConTrolled Over Pressure (CT-OP) process are used for the winding, and the critical current at 77.3 K and self-field is in the range of 174–185 A. 28 double-pancake coils are resistively connected in series by copper terminals. Highcritical current tape is used for top and bottom double-pancake coils, since the magnetic field normal to the tape surface ishighest at the top and bottom of the magnet. Two iron plates at top and bottom of the magnet are used for reduction of thenormal component of magnetic field to the Bi-2223 tape, since the total performance of the magnet is determined by theminimum critical current at maximum normal magnetic field component to the tape. The inner bore diameter of the magnetis 92 mm. And the homogeneity of magnetic field of long-axis direction in 50 mmφ × 100 mm length is within 3%. Themaximum magnetic field at the center of the bore is over 1.0 T at 77.3 K.Proceedings of the Cryogenic Engineering Conference (2013) , June 17–21, 2013, Anchorage, Alaska, US

Evaluation of Critical Current Density of FeAs-based Superconductors

In this review paper, we report the characteristics of the critical current density in FeAs based superconductors which is newly discovered by Hosono group of Tokyo Institute of Technology on 2008. Since the many specimens in present stage are not single crystals, there are two kinds of critical current density observed in the specimens which are so-called local and global critical current densities. Therefore, it is necessary to evaluate both kinds of critical current densities. The history effect in which the global critical current density shows different values in increasing and decreasing magnetic field is also observed when the specimens have the local and the global critical current densities. The wire which critical current is 180 A is successfully developed with using the knowledge of abovementioned characteristics of two kinds of critical current densities and the history effect

Enhancement of critical current density and flux pinning in Bi-2212 thick films due to MgO addition

In order to substitute cheaper sheath materials for Ag, Bi-2212 superconducting thick films grown on oxidized Ni substrates were prepared by using a normal partial melt process. 0-5 vol% of fine MgO particles were doped in Bi-2212 phase during the fabrication for the purpose of enhancement of the critical current density (J/sub c/) in Bi-2212. The samples were analyzed with the assistances of X-ray diffractometer (XRD) and electron probe microanalyzer (EPMA). The critical temperature and J/sub c/ were measured by using the conventional resistive method (4-probe method). An apparent improvement in J/sub c/ characteristic was observed in the samples with fine MgO particles doped. The J/sub c/ value in the 5 vol% MgO doped sample reached to the level comparable with that in other Ag-sheathed samples. Furthermore, the irreversibility field was confirmed to be largely enhanced by the addition of MgO particles. The pin parameters derived from the scaling behavior of pinning force density turned out to be similar to those predicted in the case of normal precipitate flux pinning, indicating that MgO particles in Bi-2212 act as effective pinning centers

Noninvasive Portable Hemoglobin Concentration Monitoring System Using Optical Sensor for Anemia Disease

Anemia is a condition in which red blood cells are not able to carry adequate oxygen to the body’s tissues, and is widely found in nearly a quarter of the world population. The typical method to screen for the iron-deficiency anemia, which is the major anemia found in the world, is to implement a blood test called a complete blood count (CBC). However, even though this test gives a highly accurate result, it requires an invasive blood drawing and lab analyzing which could potentially cause physical pain, high risk of infection and take a long time to analyze. Therefore, this research presents an alternative method using an optical technique to measure hemoglobin concentration, which is the common indicator for diagnosing anemia. The light absorbance of the oxyhemoglobin at the wavelength of 660 nm and the deoxyhemoglobin at the wavelength of 880 nm were measured using the MAX30100 sensor. These wavelengths of light are obtained from red and infrared (IR) LEDs. The concept is based on the different absorption coefficients of blood at different electromagnetic wavelengths. This fact is used to indirectly calculate the hemoglobin concentration of blood through the modified Beer–Lambert law. Moreover, the result has been further converted to absolute hemoglobin concentration using a calibration curve derived from the cyanmethemoglobin test, which is the regular method for hemoglobin determination. Besides, the android application was also provided which can wirelessly record or monitor the data. The experiment shows that an accuracy of 90.9% can be achieved by our proposed noninvasive method. Therefore, the noninvasive portable hemoglobin concentration monitoring by the optical sensor has an acceptable result when compared with the invasive method, with less pain and lower risk of infection, as well as shorter processing time

AC Magnetic Flux Profile and Critical Current Density Obtained by Campbell\u27s Method in Polycrystalline MgB2

In this study, we focused on the estimation of the global critical current density, super-current path, grain connectivity and their relationships with the faults volume fraction in the MgB2 bulks prepared by a modified PIT (powder in tube) method. Campb

Correlation between the Signal Intensity Alteration of Infrapatellar Fat Pad and Knee Osteoarthritis: A Retrospective, Cross-Sectional Study

Infrapatellar fat pad (IPFP) inflammation is a common pathological manifestation in knee osteoarthritis (OA). However, the significance of IPFP signal intensity alteration for clinical diagnosis and treatment of knee OA needs further research. We assessed IPFP signal intensity alteration (0–3), IPFP maximum cross-sectional area (CSA) and IPFP depth, meniscus injury, bone marrow edema, and cartilage injury from magnetic-resonance imaging (MRI) in 41 non-KOA patients (K-L grade 0 and grade I) and 68 KOA patients (K-L grade 2,3 and 4). We found that IPFP signaling was altered in all patients with KOA whose alteration was closely related to the K-L grading. We found that the IPFP signal intensity was increased in most OA patients, especially the ones in the late stage. There were significant differences in IPFP maximum CSA and IPFP depth between groups in KOA and non-KOA patients. Moreover, Spearman correlation analysis showed that IPFP signal intensity was moderately positively correlated with age, meniscal injury, cartilage injury, and bone marrow edema, and negatively correlated with height, while not correlated with visual analogue scale (VAS) scoring and body mass index (BMI). In addition, women have higher IPFP inflammation scores on MRI than men. In conclusion, IPFP signal intensity alteration is associated with joint damage in knee OA, which may have clinical significance for diagnosing and treating KOA

Enhancement of critical current density and flux pinning in Bi-2212 thick films due to MgO addition

In order to substitute cheaper sheath materials for Ag, Bi-2212 superconducting thick films grown on oxidized Ni substrates were prepared by using a normal partial melt process. 0-5 vol% of fine MgO particles were doped in Bi-2212 phase during the fabrication for the purpose of enhancement of the critical current density (J/sub c/) in Bi-2212. The samples were analyzed with the assistances of X-ray diffractometer (XRD) and electron probe microanalyzer (EPMA). The critical temperature and J/sub c/ were measured by using the conventional resistive method (4-probe method). An apparent improvement in J/sub c/ characteristic was observed in the samples with fine MgO particles doped. The J/sub c/ value in the 5 vol% MgO doped sample reached to the level comparable with that in other Ag-sheathed samples. Furthermore, the irreversibility field was confirmed to be largely enhanced by the addition of MgO particles. The pin parameters derived from the scaling behavior of pinning force density turned out to be similar to those predicted in the case of normal precipitate flux pinning, indicating that MgO particles in Bi-2212 act as effective pinning centers