268 research outputs found

    Producers' Cooperatives; Experience and Lessons from India

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    After attaining independence in 1947; India opted for a mixed type of economy in order to accelerate economic development. The ownership of the means of production was to remain in the private sector. The public sector was to support the growth of private economic activity. A third, cooperative sector was to be strengthened to help the numerous small producers. Investments in the public sector were directed by introducing five-year plans

    Optical properties of calcium aluminate phosphors

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    Thermoluminescence properties of CaAl2O4 was studied. It was found that firstly the TL intensity increases with increase in UV irradiation time and it attains a maximum value for 20 minute irradiation time. TL intensity decreases with further increase in irradiation time

    Sol gel synthesis and photoluminescence study of Eu3+ doped SnO2

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    Tin oxide(IV) nanophosphor doped with europium had been prepared by sol-gel technique using SnCl4 as precurser. XRD, IR, SEMand TEM analyses were used for characterization of SnO2:Eu3+. The XRD analysis shows that well crystallized tetragonal rutile SnO2:Eu3+ can be obtained by this method and the crystal size was about 15-20nm as an average for the sample calcined at 400ºC for 2h. The evolution of the most important functional groups during the steps involved in this synthesis route is explained in view of the results obtained with FTIR and XRD.  A spherical like morphology of the prepared  SnO2 nanoparticles was observed in the SEM and TEM studies. The SnO2 nanoparticles show stable photoluminescence emission intensity at 612 nm (5D0/7F2) of the Eu3+ ions activated SnO2 nanocrystals  This paper discuss the mechanistic approach of origin of luminescence in SnO2

    Thermoluminescence of ï§-irradiated SrAl2O4:Dy

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    Thermoluminescence (TL) properties of ï§-irradiated Strontium Aluminate doped with Dy (10% molar concentration) was studied. The phosphor was synthesized by combustion method using urea as a reducer at initiating temperature of 600oC.  Dy doped SrAl2O4 is a good dosimeter having linear response upto 2360 Gy of ï§-dose. The kinetic parameter have been calculated using Chen’s glow curve method

    Charged State of a Spherical Plasma in Vacuum

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    The stationary state of a spherically symmetric plasma configuration is investigated in the limit of immobile ions and weak collisions. Configurations with small radii are positively charged as a significant fraction of the electron population evaporates during the equilibration process, leaving behind an electron distribution function with an energy cutoff. Such charged plasma configurations are of interest for the study of Coulomb explosions and ion acceleration from small clusters irradiated by ultraintense laser pulses and for the investigation of ion bunches propagation in a plasma

    Effect of firing temperature on the particles size of Gd2O3: Eu doped nanophosphors

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    The paper reports that synthesis and characterization of Eu2+ doped Gd2O3 nanophosphors prepared by combustion synthesis. It has been reported that the effect of synthesis temperature on particle size dependence phenomenon of rare earth doped nanophosphors. The sample was characterized by XRD pattern and FTIR study. Synthesized sample shows cubic structure verified by the XRD results.  Size of the particle was caculated by scherer equation the avarage size obtained 15, 23 and 55 at 4000C, 5000C and 6000C respectively. In this synthesis urea used as a fuel for created reducing atmosphere during sample preparation.&nbsp

    Thermoluminescence and Mechanoluminescence studies of (Cd0.95 Zn0.05)S: Ag doped phosphor

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    Through the execution of experimental investigation, mechanoluminescence of (Cd,Zn)S: Ag phosphor was studied which is synthesized by solid state reaction. In the observation, the peak value of ML depends on different concentration. It is seen that ML intensity increases with Ag ion concentration in (Cd, Zn)S phosphor. The peak value of TL depends on the different UV-irradiation time. It is seen that as UV-irradiation exposure increases the TL intensity also increases

    Mechanoluminescence properties of SrAl2O4: Tb3+ phosphor

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    Through the execution of experimental investigation, Mechanoluminescence of SrAl2O4:Tb3+ phosphor was studied which is synthesized by combustion method. In the observation, the peak value of ML depends on the different impact velocity. It was seen that at 55 cm height, the maximum peak of ML is obtained.&nbsp

    Idiopathic osteonecrosis of the medial tibial plateau

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    Osteonecrosis of the medial tibial plateau is characterized by acute pain on the medial aspect of the knee. Progression can lead to articular collapse and requires early diagnosis and treatment. We studied seven patients affected of idiopathic osteonecrosis of the tibial plateau. The mean age was 62 years and the mean follow-up 42 months. We performed roentgenograms in all patients, bone scans in three patients and magnetic resonance image (MRI) in five. MRI shows T1-weighted low-intensity signal and T2-weighted high-intensity signal with a surrounding area of intermediate low-intensity signal. An increased focal uptake was seen at bone scan. Histological findings showed necrotic bone with empty lacunae. Surgical treatment consisted of tibial subchondral drilling in four patients-two of them by failure of conservative treatment, and a total knee arthroplasty in other two. One patient had a satisfactory evolution with conservative treatment. Idiopathic osteonecrosis of the tibial plateau must be considered in elderly patients with knee pain over the medial tibial plateau. At early stages, decompression with tibial drilling must be considered. This procedure allows a prompt and effective relief of symptom

    Reproducibility of patient setup by surface image registration system in conformal radiotherapy of prostate cancer

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    <p>Abstract</p> <p>Background</p> <p>The reproducibility of patient setup for radiotherapy is based on various methods including external markers, X-rays with planar or computerized image acquisition, and, more recently, surface matching imaging. We analyzed the setup reproducibility of 16 patients affected by prostate cancer who underwent conformal radiotherapy with curative intent by using a surface image registration system.</p> <p>Methods</p> <p>We analyzed the setup reproducibility of 16 patients affected by prostate cancer candidates for conformal radiotherapy by using a surface image registration system. At the initial setup, EPID images were compared with DRRs and a reference 3D surface image was obtained by the AlignRT system (Vision RT, London, UK). Surface images were acquired prior to every subsequent setup procedure. EPID acquisition was repeated when errors > 5 mm were reported.</p> <p>Results</p> <p>The mean random and systematic errors were 1.2 ± 2.3 mm and 0.3 ± 3.0 mm along the X axis, 0.0 ± 1.4 mm and 0.5 ± 2.0 mm along the Y axis, and 2.0 ± 1.8 mm and -0.7 ± 2.4 mm along the Z axis respectively. The positioning error detected by AlignRT along the 3 axes X, Y, and Z exceeded the value of 5 mm in 14.1%, 2.0%, and 5.1% measurements and the value of 3 mm in 36.9%, 13.6% and 27.8% measurements, respectively. Correlation factors calculated by linear regression between the errors measured by AlignRT and EPID ranged from 0.77 to 0.92 with a mean of 0.85 and SD of 0.13. The setup measurements by surface imaging are highly reproducible and correlate with the setup errors detected by EPID.</p> <p>Conclusion</p> <p>Surface image registration system appears to be a simple, fast, non-invasive, and reproducible method to analyze the set-up alignment in 3DCRT of prostate cancer patients.</p
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