Computation of detective quantum efficiency of medical x-ray radiographic screen-films

Detective quantum efficiency (DQE) is one of the important measures in the assessment of image quality and detector performance. Detective quantum efficiency of radiographic screen-film depends on noise power spectrum (NPS), modulation transfer function (MTF), gamma of the film and photon fluence. DQE of two types of screenfilms namely Lanex Regular/T-Mat G/RA and Lanex Regular/T-Mat L/RA were determined using MTF and NPS data, separately. For calculation of gamma of the film, characteristic curves of each screen-film were used to find slope of straight part of the curves. Photon fluence was estimated using published literature. DQE of the screenfilms were computed by MATLAB program for three optical densities 0.7, 1.0 and 1.4. The X-ray source was at 81 kVP. MTF of Lanex Regular/T-Mat G/RA was found to be slightly better than Lanex Regular/T-Mat L/RA for spatial frequencies between 0.5 and 3.0, but it was found to be slightly better MTF for Lanex Regular/T-Mat L/RA for spatial frequencies between 5.2 and 7.0. NPS of Lanex Regular/TMat G/RA was found one and a half times bigger than Lanex Regular/T-Mat L/RA. DQE comparison of these two types of screen-films was made. The results show Lanex Regular/T-Mat G/RA has better DQE than Lanex Regular/T-Mat L/RA, at low frequencies

Preparation and characterization of rice starch based solid polymer electrolytes for dye−sensitized solar cell application / Mohammad Hassan Khanmirzaei

Biodegradable polymers have economic and environmental benefits due to cheap in cost and biodegradability. Utilizing environmental friendly polymers in polymer electrolytes and electronics field can be good replacement for some harmful existing materials and admirable category for green energy applications such as solar cells, specifically, dye sensitized solar cells, super capacitors, batteries, etc. Solid polymer electrolyte (SPE) systems based on rice starch as a biodegradable polymer, three iodide salts namely lithium iodide, ammonium iodide and sodium iodide, and two ionic liquids namely 1-methyl-3-propylimidazolium iodide (MPII) and 1-hexyl-3-methylimidazolium iodide (HMII) were studied for dielectric properties and solar cell applications in this research. Polymer electrolytes were prepared using solution cast technique. The ionic conductivity and temperature-dependent conductivity and dielectric behavior were analyzed in this work. The highest ionic conductivities were achieved in SPE systems after addition of ionic liquid. The solid polymer electrolytes were characterized for dielectric, structural and thermal properties using EIS, FTIR, XRD, TGA and DSC. In temperature-dependent study, all SPEs follow the Arrhenius thermal activated model. In structural study using FTIR and XRD, complexations between polymer, salt and ionic liquid were confirmed for all SPEs. Furthermore, Thermal studies using TGA and DSC thermograms demonstrated that decomposition temperature (Tdc) and glass transition temperature (Tg) for rice starch shift upon complexation with iodide salt and ionic liquid. Dye sensitized solar cells (DSSCs) were fabricated using SPE systems with highest ionic conductivities. TiO2 paste was doctor-bladed on FTO substrate and sintered at 450 ℃ as photo-electrode. The photo-electrode was immersed in Ruthenium based dye (N719) for 24 hr. Platinum coated FTO was used as the counter electrode. iv Solid polymer electrolytes were sandwiched between two photo and counter electrode with the configuration of Glass/FTO/TiO2/N719-Dye/Solid polymer electrolyte/Pt/FTO/Glass. The fabricated DSSCs were analyzed for energy conversion using Sun simulator with white light illumination of 1000 (W m−2) defined as incident light power. The DSSCs show significant conversion energy efficiencies for solid biopolymer based solar cells as green energy source

Vermicompost enrichment using organic wastes: Nitrogen content and mineralization

Purpose This study performed a feasibility assessment of nitrogen enrichment by some organic wastes through vermicomposting as well as its release as a bioavailable form over time. Methods Soybean and canola wastes as well as the dairy blood powder of industrial slaughterhouse were used as organic wastes to enrich the vermicompost. Composted materials were incubated for nitrogen mineralization kinetic assessment by adjusting moisture content to 50% at 30 ˚C for 80 days. During the incubation, moisture was maintained by weighing. Subsamples were collected after 1, 5, 10, 20, 40, 60, and 80 days of incubation. Results Among the treatments, those for 25% dairy blood powder contained the highest nitrogen content (4.95 and 3.70% for chicken and cow blood powder, respectively). Nitrogen mineralization through 80 days of incubation ranged from 2.23% (for 50% canola waste treatment) to 2.57% (for 25% blood powder) of the total nitrogen. The mineralization rate ranged from 4.24 and 3.62 mg kg-1 day-1 for the compost containing 25% chicken and cow blood powder, respectively, to 0.94 and 0.84 mg kg-1 day-1 in canola and soybean waste, respectively, whereas those for the control treatment equaled 0.81 mg kg-1 day-1. Conclusion Composts containing 25% blood powder were acceptable in terms of quantity and nitrogen release over time, and can serve as a reliable source of available nutrients in the soil

Hydroxypropyl Cellulose Based Non-Volatile Gel Polymer Electrolytes for Dye-Sensitized Solar Cell Applications using 1-methyl-3-propylimidazolium iodide ionic liquid

Gel polymer electrolytes using imidazolium based ionic liquids have attracted much attention in dye-sensitized solar cell applications. Hydroxypropyl cellulose (HPC), sodium iodide (NaI), 1-methyl3- propylimidazolium iodide (MPII) as ionic liquid (IL), ethylene carbonate (EC) and propylene carbonate (PC) are used for preparation of non-volatile gel polymer electrolyte (GPE) system (HPC:EC:PC:NaI:MPII) for dye-sensitized solar cell (DSSC) applications. The highest ionic conductivity of 7.37 x 10(-3) S cm(-1) is achieved after introducing 100% of MPII with respect to the weight of HPC. Temperature-dependent ionic conductivity of gel polymer electrolytes is studied in this work. XRD patterns of gel polymer electrolytes are studied to confirm complexation between HPC polymer, NaI and MPII. Thermal behavior of the GPEs is studied using simultaneous thermal analyzer (STA) and differential scanning calorimetry (DSC). DSSCs are fabricated using gel polymer electrolytes and J-V characteristics of fabricated dye sensitized solar cells were analyzed. The gel polymer electrolyte with 100 wt.% of MPII ionic liquid shows the best performance and energy conversion efficiency of 5.79%, with short-circuit current density, open-circuit voltage and fill factor of 13.73 mA cm(-2), 610 mV and 69.1%, respectively

Performance enhancement of poly (vinylidene fluoride-co-hexafluoro propylene)/polyethylene oxide based nanocomposite polymer electrolyte with ZnO nanofiller for dye-sensitized solar cell

Nanocomposite polymer electrolytes (NCPEs) were prepared by blending poly (vinylidene fluoride-co-hexafluoro propylene) copolymer (PVdF-HFP) and polyethylene oxide (PEO) polymers and incorporation of ZnO inorganic nanofiller (PVdF-HFP:PEO:EC:PC:NaI:I2:ZnO). The highest ionic conductivity value of 8.36 mS cm−1 was recorded when 3 wt.% of ZnO inorganic nanofiller was incorporated into the NCPE system. Temperature-dependant ionic conductivity behaviour of NCPEs was analysed and proven to follow the Arrhenius thermal activated model. Structural studies of NCPEs were carried out using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy analysis. NCPEs were used to fabricate Dye-sensitized solar cells (DSSCs). Enhancements in the solar light to electricity conversion efficiency (η) of DSSCs were observed in the presence of ZnO inorganic nanofiller in the NCPE system and NCPE with 3 wt.% ZnO represented the highest η of 7.33% under full sun irradiation

Novel poly(vinylidene fluoride-co-hexafluoro propylene)/polyethylene oxide based gel polymer electrolyte containing fumed silica (SiO2) nanofiller for high performance dye-sensitized solar cell

Novel gel polymer electrolytes (GPEs) are prepared using poly(vinylidene fluoride-co-hexafluoro propylene) copolymer (PVdF-HFP) and polyethylene oxide (PEO) in presence of fumed silica nanofiller with the designated system of PVdF-HFP:PEO:EC:PC:NaI:SiO2:I2. GPEs are examined using electrochemical impedance spectroscopy (EIS) and the highest ionic conductivity of 8.84 mS cm−1 is achieved after incorporation of 13 wt.% of fumed silica (SiO2). Temperature-dependent ionic conductivity study confirms that GPE system follows Arrhenius thermal activated model. GPEs are characterized for structural studies using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. GPEs are used to fabricate dye-sensitized solar cells (DSSCs) and tested under 1 Sun irradiation, obtaining the highest energy conversion efficiency of 9.44% after the incorporation of 13 wt.% fumed silica. Cyclic voltammetry has been performed to analyse electrochemical properties of gel polymer electrolytes

Quasi-solid-state agar-based polymer electrolytes for dye-sensitized solar cell applications using imidazolium-based ionic liquid

Agar as a natural polymer is used to prepare quasi-solid-state polymer electrolytes (QSPEs). Two different iodide salts namely sodium iodide (NaI) and potassium iodide (KI) are incorporated. To enhance the ionic conductivity of the QSPE system, 1-methyl-3-propylimidazolium iodide (MPII) ionic liquid is added. The highest ionic conductivity of 1.48 × 10−3 S cm−1 was achieved after addition of 50 wt.% of KI and 3.0 g of MPII ionic liquid. QSPEs are studied for temperature-dependent ionic conductivity behavior. QSPEs are studied for structural properties using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The structural studies revealed that the complexation between agar polymer, iodide salts, and MPII ionic liquid has occurred. QSPEs are sandwiched between counter and working electrodes to fabricated DSSC and analyzed under sun simulator. The highest efficiency of 2.16% is achieved with incorporation of 3.0 g MPII ionic liquid

Presence of NaI in PEO/PVdF-HFP blend based gel polymer electrolytes for fabrication of dye-sensitized solar cells

Poly(vinylidene fluoride-co-hexafluoro propylene) copolymer (PVdF-HFP) and polyethylene oxide (PEO) blend gel polymer electrolytes (GPEs) containing ethylene carbonate (EC) and propylene carbonate (PC) as solvent with different concentrations of sodium iodide (NaI) salt are prepared. Effect of sodium iodide (NaI) on the gel polymer electrolyte system is investigated by using electrochemical impedance spectroscopy (EIS), temperature-dependence ionic conductivity, X-ray diffraction (XRD) and FTIR studies. The highest ionic conductivity value for the gel polymer electrolytes are 6.38 mS cm−1 in the presence of 100 wt% of sodium iodide (NaI) salt with respect to weight of PEO/PVdF-HFP polymer blend. The temperature-dependent ionic conductivity study indicates that the gel polymer electrolyte system follows the Arrhenius model. Dye-sensitized solar cells (DSSCs) are fabricated using gel polymer electrolytes and tested under Sun simulator. The highest energy conversion efficiency value of 5.67% is obtained after the addition of 100 wt% of sodium iodide (NaI) salt