Surendra Poonia

Transition assignments to Lβ2 satellites in X-ray emission spectra of higher Z elements

Abstract The satellite spectra arising due to L 3 M x –M x N 4,5 ( x =1–5) transition array in X-ray emission spectra of 74 W, 76 Os, 78 Pt, 80 Hg, 82 Pb, 88 Ra and 90 Th, have been calculated using available HFS data on K–LM and L–MN Auger transition energies. The agreement between the calculated and measured energies, that between calculated and measured separations in energies and the consideration of the relative probabilities of all the L 3 M x –M x N 4,5 transitions have been used as the basis for deciding the origin of the satellites. It has been established that two satellites observed in the Lβ 2 region of the X-ray spectra of various elements and named β 2 I and β 2 II in order of increasing energy are mainly emitted by L 3 M 4,5 –M 4,5 N 4,5 transitions. It is observed that the satellite β 2 I in the spectra of elements with Z =74–76 has been assigned to the superposition of 3 F 4 – 3 G 5 and 3 F 4 – 3 D 3 transitions and that it must be the most intense of all these satellites. The same transitions have been proved to be the main origin of the satellite, β 2 II , reported in the range Z =78–90. Further, the satellite β 2 I , reported in the spectra of elements with Z= 74 W to 76 Os, has been associated with the transitions 3 D 3 – 3 F 4 and 1 D 2 – 1 F 3 . Finally, the line β 2 II , reported in the spectra of elements Z =74–76, has been assigned to the 1 F 3 – 1 G 4 transition. The possible contributions of other transitions of the L 3 M x –M x N 4,5 ( x =1–5) array having intensities comparable with the above transitions, and the corresponding lines, which have not yet been observed, have also been discussed.

Transition assignments to Lβ2 satellites in X-ray emission spectra of middle-Z elements

Abstract The satellite spectra arising due to L 3 M x –M x N 4,5 ( x =1–5) transition array in X-ray emission spectra of 42 Mo, 44 Ru, 46 Pd, 48 Cd, 50 Sn and 52 Te, have been calculated using available HFS data on K–LM and L–MN Auger transition energies. The agreement between the calculated and measured energies, that between calculated and measured separations in energies and the consideration of the relative probabilities of all the L 3 M x –M x N 4,5 transitions have been used as the basis for deciding the origin of the satellites. It has been established that three satellites observed in the Lβ 2 region of the X-ray spectra of various elements and named β 2 (b) , β 2 II and β 2 (c) in order of increasing energy are mainly emitted by L 3 M 4,5 –M 4,5 N 4,5 transitions. It is observed that only β 2 (b) in all these spectra can be assigned to superposition of 3 F 4 – 3 G 5 and 3 F 4 – 3 D 3 transitions and that this must be the most intense of all these satellites. Each of the remaining two satellites is found to have different origin in different elements. So is the case with the line β 2 I which has been observed on lower energy side of β 2 (b) and has been associated with an L 3 M 4,5 –M 4,5 N 4,5 transition in some elements. The suitable transitions to all these lines have been presented.

Development of Phase Change Material-Based Temperature Regulation Facility Inside Protected Agriculture Structure

In arid agriculture, protected cultivation inside structures with polythene or shade net as covered material may be found beneficial to avoid aberrant weather conditions. However, significant amount of heat load is generated inside the structure due to high solar irradiation and trapping of outgoing longwave radiation due to protected covers, which lead to uncongenial conditions for sustainable plant growth. With a view to regulating temperature inside the protected cultivation structure, phase change material (PCM)-based temperature regulation facility was tried to develop through laboratory trials and experiments. Mixtures of paraffin liquid and paraffin wax in different ratios were prepared in the laboratory and heat change of the mixture material was recorded during heating and cooling process in a controlled water bath experimental setup. A mixture of paraffin liquid and wax in the ratio 10:1 was found suitable as a phase change material with melting temperature at about 35–38 °C. In the second stage, two heat exchanger structures consisting of GI sheet tank of 6.5 L capacity and aluminium fins attached at both sides of the tank for better heat transfer with air were designed and fabricated and these were tested inside small experimental structures with fibre glass sheet casing and covers. A decrease of inside temperature by 8–10 °C has been observed inside prototype structure with the incorporation of PCM material compared to one without it. Subsequently, the system was kept inside the PV clad enclosure (13.5 m2) and the performance of the enclosure was studied with chilli crop grown inside. The amount of heat stored by a single PCM storage system with 2.5 kg PCM materials was found about 1100–1200 kJ. An estimate indicates that it is sufficient to reduce the inside temperature by 1 °C for four hours if number of air change rate is 30 per hour. However, long-term trials are required to ascertain number of cycles of heating and cooling of the material.

Design, Development and Performance Evolution of a Low-Cost Solar Dryer

Considerable amount of fruits and vegetables have been wasted due to non-availability of appropriate processing facilities in farmers field, in spite of high production in India with second rank in the world. A little of total fruit and vegetable productions in the country have been processed in industries. It has been noted that food crisis in most parts of the world is due to non-availability of processing and preserving facility rather than due to low production. Spoilage of fruits and vegetables can be reduced by drying and preserving them by suitable solar devices. Keeping in mind this requirement, a simple solar dryer has been fabricated at ICAR-CAZRI, Jodhpur. The dryer comprises a drying tray (0.75 m × 0.53 m) made of wooden frame and SS wire mesh and a glass sheet (4 mm thick) fitted on a wooden frame and a couple of hinges with opening and closing arrangements. Suitable openings for entry of ambient air and exit of water vapour have also been provided. The cost of the dryer is about Rs. 800. The drying tray serves dual purpose of solar collector and drying chamber. The maximum stagnation temperature observed inside the drying chamber was 63 °C on loading of 3 kg ber (Ziziphus sp.). It was 49 °C, when the outside ambient temperature was 27 °C on a clear sunny day (from 10 am to 4 pm) in the month of December–January. For drying of 3 kg ber fruits to a final weight of 1 kg using the developed dryer, it took about 7–8 days. It has been observed that the drying time for Ziziphus (ber) decreased by 50% in comparison to open sun drying. The developed dryer was also successfully tested to dry spinach (Spinacia oleracea), grated aonla (Phyllanthus emblica) and beetroot (Beta vulgaris). This solar dryer would be very useful for small and marginal farmers.

Design development and performance evaluation of photovoltaic/thermal (PV/T) hybrid solar dryer for drying of ber (Zizyphus mauritiana) fruit

Abstract This research paper describes the drying kinetics of ber (Zizyphus mauritiana) fruit and economic evaluation of hybrid photovoltaic/thermal (PV/T) solar dryer fabricated using locally available materials, e.g. galvanized iron sheet, glass, PV panel and fan. Ber fruits were dried to the safe level moisture content (20%) in a period of 240 h with the drying load of 18 kg. Four mathematical models were evaluated to predict the behaviour of ber (Zizyphus mauritiana) drying in a combined hybrid PV/T solar dryer. Experimental data of moisture ratio (MR) and temperature obtained from dryer were fitted to the four empirical drying models. The performance of the drying model was compared based on their statistical parameters: coefficient of determination (R2), root mean square error (RMSE) and reduced chi-square (χ2) between the observed and predicted MR. The logarithmic model was found to be the most suitable for describing the thin layer drying behaviour of ber (Zizyphus mauritiana). The effective moisture diffusivity was 3.34 × 10−7 m2/s and the efficiency of this dryer was found to be 16.7%. The developed hybrid PV/T drying system produces better quality products in shorter time by the efficient use of solar energy. The economic evaluation of the hybrid photovoltaic thermal (PV/T) solar dryer revealed that high value of IRR (54.5%) and low value of payback period (2.26 Years) make the dryer unit cost-efficient ensuring its economic viability.

L/spl alpha//sub 2/ satellites in X-ray emission spectra of higher Z elements

Summary form only given. The X-ray satellite spectra arising due to the 2p/sub 3/2//sup -1/3x/sup -1/-3x/sup -1/3d/sup -1/ (x/spl equiv/s, p, d) transition array, in elements with Z=73 to 90, have been calculated. While the energies of various transitions of the array have been determined using available Hartree-Fock-Slater data on 1s/sup -1/-2p/sup -1/3x/sup -1/ and 2p/sub 3/2//sup -1/-3x/sup -1/,3x/sup -1/ Auger transition energies and their relative intensities have been estimated by considering cross-sections of singly ionized 2x/sup -1/ (x /spl equiv/ s, p) states and then of subsequent Coster-Kronig and shake off processes. The calculated spectra have been compared with the measured satellite energies in L/spl alpha/ spectra. Their intense peaks have been identified as the observed satellite lines. The one to one correspondence between the peaks in calculated spectra and the satellites in measured spectra has been established on the basis of the agreement between the separations in peak energies and those in the measured satellite energies. It has been established that one satellite observed in the L/spl alpha//sub 2/ region of the X-ray spectra of various elements and named /spl alpha//sub s/ in order of increasing energy are mainly emitted by 2p/sub 3/2//sup -1/3d/sup -1/-3d/sup -2/ transitions. It is observed that the satellite /spl alpha//sub s/ in all these spectra can be assigned to the superposition of three intense transitions namely /sup 3/P/sub 1/-/sup 3/D/sub 1/, /sup 3/D/sub 2/-/sup 3/D/sub 3/ and /sup 3/D/sub 2/-/sup 3/D/sub 1/. The three remaining satellites in /sup 80/Hg namely La/sub 13/, La/sub 14/ and La/sub 17/ are found to have different origin in different elements. The possible contributions of other transitions of the 2p/sub 3/2//sup -1/3x/sup -1/-3x/sup -1/3d/sup -1/ (x/spl equiv/ s, p, d) array having appreciable intensities have also been discussed.