757 research outputs found

    Low temperature study of field induced antiferro-ferromagnetic transition in Pd doped FeRh

    Full text link
    The first order antiferromagnetic (AFM) to ferromagnetic (FM) transition in the functional material Fe49(Rh0.93Pd0.07)51 has been studied at low temperatures and high magnetic fields. We have addressed the non-monotonic variation of lower critical field required for FM to AFM transition. It is shown that critically slow dynamics of the transition dominates below 50 K. At low temperature and high magnetic field, state of the system depends on the measurement history resulting in tunable coexistence of AFM and FM phases. By following cooling and heating in unequal magnetic field (CHUF) protocol it is shown that equilibrium state at 6 Tesla magnetic field is AFM state. Glass like FM state at 6 T (obtained after cooling in 8 T) shows reentrant transition with increasing temperature; viz. devitrification to AFM state followed by melting to FM state.Comment: 8 pages, 7 figure

    ACHIEVING AVAILABILITY AND DATA INTEGRITY PROOF IN HIERARCHICAL ATTRIBUTE ENCRYPTION SCHEME USING HYBRID CLOUD

    Get PDF
    It has been widely observed that the concept of cloud computing has become one of the major theory in the world of IT industry. Data owner decides to release their burden of storing and maintaining the data locally by storing it over the cloud. Cloud storage moves the owner’s data to large data centers which are remotely located on which data owner does not have any control. However, this unique feature of the cloud poses many new security challenges. One of the important concerns that need to be addressed is access control and integrity of outsourced data in cloud. Number of schemes has been proposed to achieve the access control of outsourced data like hierarchical attribute set based encryption [HASBE] by extending cipher-text-policy attribute set based encryption [CP-ABE]. Even though HASBE scheme achieves scalability, flexibility and fine grained access control, it fails to prove the data integrity in the cloud. Hence integrity checking concept has been proposed for HASBE scheme to achieve integrity. Though the scheme achieves integrity it fails to provide the availability of data to the user even when fault had occurred to data in the cloud. However, the fact that owner no longer have physical possession of data indicates that they are facing a potentially formidable risk for missing or corrupted data, because sometimes the cloud service provider deletes the data which are either not used by client from long-time and which occupies large space in the cloud without the knowledge or permission of data owner. Hence in order to avoid this security risk, in this paper we propose a hybrid cloud concept. Hybrid cloud is a cloud computing environment in which an organization provides and manages some internal resources and external resources. A hybrid cloud is a composition of at least one private cloud and at least one public cloud. This concept provides the availability and data integrity proof for HASBE scheme

    Real Space Visualization of Thermomagnetic Irreversibility within Supercooling and Superheating Spinodals in Mn1.85Co0.15SbMn_{1.85}Co_{0.15}Sb using Scanning Hall Probe Microscopy

    Full text link
    Phase coexistence across disorder-broadened and magnetic-field-induced first order antiferromagnetic to ferrimagnetic transition in polycrystalline Mn1.85Co0.15SbMn_{1.85}Co_{0.15}Sb has been studied mesoscopically by Scanning Hall Probe Microscope at 120K and up to 5 Tesla magnetic fields. We have observed hysteresis with varying magnetic field and the evolution of coexisting antiferromagnetic and ferrimagnetic state on mesoscopic length scale. These studies show that the magnetic state of the system at low field depends on the path followed to reach 120 K. The low field magnetic states are mesoscopically different for virgin and second field increasing cycle when 120 K is reached by warming from 5K, but are the same within measurement accuracy when the measuring temperature of 120K is reached from 300K by cooling

    Borderline Ovarian Malignancies : A Single Institute Retrospective Study.

    Get PDF
    Background: Borderline ovarian tumors are histologically characterized as epithelial tumors with a stratified growth pattern but without destructive stromal invasion. Little is known about the histological subtypes and outcome, role of fertility sparing surgery and role of postoperative therapy in advanced stage in Indian scenario. While there is ample data in the world literature about this disease, prognosis in Indian patients is largely unknown due to dearth of studies in our setting. Objective: To study the demographic profile, clinical features, imaging, treatment and outcome of borderline ovarian tumors. Methods: This is a retrospective study of eighty seven patients with pathologically proven diagnosis of borderline ovarian tumor, diagnosed and treated from January 2006 to October 2011 at our institution. Most patients underwent surgical staging which incuded total abdominal hysterectomy and bilateral salphingo-oophorectomy, infracolic omentectomy, bilateral pelvic and para aortic lymphadenectomy. Young patients who had not completed their family underwent fertility sparing surgery. Patients with invasive metastatic implants received adjuvant chemotherapy. The outcome of these patients was correlated with stage, type of peritoneal implant, type of surgical procedure and with histological subtype. Results: At a median follow-up of 48 months, 100 percent survival was noted. One patient with stage III disease had recurrence. Conclusions: Borderline ovarian tumors occur at a younger age compared to invasive tumors. In patients with early stage disease who wish to preserve fertility, hysterectomy and contralateral oophorectomy are not necessary. Serous tumors occur at a younger age. They can be associated with invasive peritoneal implants and raised CA125 values. Majority of the serous tumors are bilateral and smaller in size compared to mucinous and endometroid tumors. Raised CA125 values did not correlate with the stage of disease. These patients have an excellent prognosis even in Indian scenario where majority of patients present with big ovarian masses

    Room temperature giant baroresistance and magnetoresistance and its tunability in Pd doped FeRh

    Full text link
    We report room temperature giant baro-resistance (≈\approx128\%) in Fe49(Rh0.93Pd0.07)51Fe_{49}(Rh_{0.93}Pd_{0.07})_{51}. With the application of external pressure and magnetic field the temperature range of giant baro-resistance (≈\approx600\% at 5K and 19.9 kbar and 8 Tesla) and magnetoresistance (≈\approx-85\% at 5K and 8 tesla) can be tuned from 5 K to well above room temperature. As the AFM state is stabilized at room temperature under external pressure, it shows giant room temperature magnetoresistance (≈\approx-55\%) with magnetic field. Due to coupled magnetic and latticel changes, the isothermal change in room temperature resistivity with pressure (in the absence of applied magnetic field) as well as magnetic field (under various constant pressure) can be scaled together to a single curve when plotted as a function of X = T + 12.8*H - 7.2*P

    Myrica Esculenta and it’s Anti-Asthmatic Property with Ayurvedic approach : A Review

    Get PDF
    Myrica esculenta is a perennial shrub, of myricaceae family. From ancient time myrica esculanta reported to be used in traditional system of medicine. Various parts of the tree bark, fruit, flower are used therapetucally including for treatment of anemia, bronchitis, cough, chronic dysentery, fever, liver complaints, nasal catarrh, piles, sores, throat complaints, tumors, ulcers, urinary discharges. This review gives us a bird’s eye view on detailed information of this plants and targeted anti-asthmatic property of plant,as per Ayurvedic view concern

    Residual stress induced stabilization of martensite phase and its effect on the magneto-structural transition in Mn rich Ni-Mn-In/Ga magnetic shape memory alloys

    Full text link
    The irreversibility of the martensite transition in magnetic shape memory alloys (MSMAs) with respect to external magnetic field is one of the biggest challenges that limits their application as giant caloric materials. This transition is a magneto-structural transition that is accompanied with a steep drop in magnetization (i.e., 'delta M') around the martensite start temperature (Ms) due to the lower magnetization of the martensite phase. In this communication, we show that 'delta M' around Ms in Mn rich Ni-Mn based MSMAs gets suppressed by two orders of magnitude in crushed powders due to the stabilization of the martensite phase at temperatures well above the Ms and the austenite finish (Af) temperatures due to residual stresses. Analysis of the intensities and the FWHM of the x-ray powder diffraction patterns reveals stabilized martensite phase fractions as 97, 75 and 90% with corresponding residual microstrains as 5.4, 5.6 and 3% in crushed powders of the three different Mn rich Ni-Mn alloys, namely, Mn1.8Ni1.8In0.4, Mn1.75Ni1.25Ga and Mn1.9Ni1.1Ga, respectively. Even after annealing at 773 K, the residual stress stabilised martensite phase does not fully revert to the equilibrium cubic austenite phase as the magneto-structural transition is only partially restored with reduced value of 'delta M'. Our results have very significant bearing on application of such alloys as inverse magnetocaloric and barocaloric materials
    • …
    corecore