Spatial variability of daily rainfall over Orissa, India, during the southwest summer monsoon season

Southwest summer monsoon rainfall over Orissa, a state of eastern India, shows characteristic spatial and temporal variability, due to the interaction of basic westerly flow with orography and the synoptic-scale monsoon disturbances developing over the northern Bay of Bengal and moving west-northwestwards along the monsoon trough. The aim of this study is to find out the main features of the spatial variability of daily monsoon rainfall over Orissa and associated synoptic systems. Empirical orthogonal function (EOF) analysis is a good tool to filter out the main components from any noise, and this was applied to daily monsoon rainfall (June-September) data of 31 uniformly distributed stations over a period of 20 years (1980-1999). The association of synoptic systems with significant EOFs has been confirmed by analysing daily synoptic systems over Orissa and its neighbourhood during the same period. The first three EOFs in S-mode may be attributed to good monsoon rainfall in association with low-pressure systems/cyclonic circulation (LPSC), like lows, depressions, cyclonic storms and cyclonic circulation extending up to the mid-tropospheric level over the northwest (NW) Bay/NW and the adjoining northeast (NE) Bay, over Gangetic West Bengal (GWB) and over Orissa/NW and the adjoining west central (WC) Bay. The fourth and fifth EOFs may be attributed to a weak monsoon condition being associated only with a monsoon trough without any embedded system and LPSC over the NE and the adjoining NW Bay respectively. Based on rotation of significant EOFs in T-mode, which gives better regionalization, Orissa consists of five homogeneous regions of daily monsoon rainfall: (i) eastern Orissa, (ii) western Orissa, (iii) northwest Orissa, (iv) north Orissa and (v) northeast Orissa. Eastern Orissa gets higher rainfall than the other regions, due to LPSC over NW Bay/NW and the adjoining NE Bay, western Orissa rainfall is due to LPSC over Orissa/NW and the adjoining WC Bay; likewise, northwest Orissa rainfall is due to LPSC over GWB, north Orissa rainfall is due to LPSC over the NE and the adjoining NW Bay, and northeast Orissa rainfall is due only to a monsoon trough without any significant embedded system over Orissa and adjoining land/sea areas

Fragmentation of a Circular Disc by Impact on a Frictionless Plate

The break-up of a two-dimensional circular disc by normal and oblique impact on a hard frictionless plate is investigated by molecular dynamics simulations. The disc is composed of numerous unbreakable randomly shaped convex polygons connected together by simple elastic beams that break when bent or stretched beyond a certain limit. It is found that for both normal and oblique impacts the crack patterns are the same and depend solely on the normal component of the impact velocity. Analysing the pattern of breakage, amount of damage, fragment masses and velocities, we show the existence of a critical velocity which separates two regimes of the impact process: below the critical point only a damage cone is formed at the impact site (damage), cleaving of the particle occurs at the critical point, while above the critical velocity the disc breaks into several pieces (fragmentation). In the limit of very high impact velocities the disc suffers complete disintegration (shattering) into many small fragments. In agreement with experimental results, fragment masses are found to follow the Gates-Gaudin-Schuhmann distribution (power law) with an exponent independent of the velocity and angle of impact. The velocity distribution of fragments exhibit an interesting anomalous scaling behavior when changing the impact velocity and the size of the disc.Comment: submitted to J. Phys: Condensed Matter special issue on Granular Medi

Inheritance of parthenocarpy in gynoecious cucumber (Cucumis sativus L.) cultivar PPC-2

The gynoecious and parthenocarpic inbred line, Pant Parthenocarpic Cucumber-2 (PPC- 2) was crossed with Indian monoecious and non-parthenocarpic cultivar Pusa Uday to develop F1, F2, B1 and B2 to determine the inheritance of parthenocarpy.The crop was grown under insect proof net house of 40 mesh. The pistillate buds were covered using butter paper bags before anthesis to prevent out-crossing.The observations were recorded separately for the development of early parthenocarpic fruits (i.e.1-7th nodes), late parthenocarpy (8th and above nodes) and non-parthenocarpic fruits. In F1 generation, out of 40 plants screened, 2 plants produced parthenocarpic fruits at lower nodes (1-7th nodes), 37 plants produced parthenocarpic fruits at upper nodes (8th and above), whereas,only 1 plant that did not produced any fruit was considered as non-parthenocarpic. The segregation of F2 population and test crosses for parthenocarpic fruit development suggested that parthenocarpy in gynoecious and parthenocarpic cucumber line PPC-2 is under the control of incomplete dominant gene

Broadband, wide-angle antireflection in GaAs through surface nano-structuring for solar cell applications

We demonstrate broadband and wide-angle antireflective surface nanostructuring in GaAs semiconductors using variable dose electron-beam lithography (EBL). Various designed structures are written with EBL on a positive EB-resist coated GaAs and developed followed by shallow inductively coupled plasma etching. An optimized nanostructured surface shows a reduced surface reflectivity down to less than 2.5% in the visible range of 450–700 nm and an average reflectance of less than 4% over a broad near-infrared wavelength range from 900–1400 nm. The results are obtained over a wide incidence angle of 33.3°. This study shows the potential for anti-reflective structures using a simpler reverse EBL process which can provide optical absorption or extraction efficiency enhancement in semiconductors relevant to improved performance in solar photovoltaics or light-emitting diodes

Ergonomics of Farm Women in Manual Paddy Threshing

Thin-layer drying experiments with Roselle (Hibiscus sabdariffa .L) were carried out in a constant temperature and humidity chamber. Four temperatures (35, 45, 55, and 65°C) and five relative humidities (30, 35, 40, 45, and 50%RH) were tested. Statistical analysis on twelve thinlayer drying model proved the superiority of two-term exponential model. The objectives of this work were to evaluate and validate the two-term exponential model; besides, examine the effects of the drying conditions on the drying rate and constant. Validation of the developed model was done using two criterions, plotting of the predicted against experimental moisture contents and the residual versus predicted moisture content. The average values of the drying constant (k) and coefficient (a) weA study was taken up to have a comparative study on the ergonomics of farm women in pedal threshing with single and double operators (N =15) and to suggest modifications for further reduction of human drudgery. The mean HR work was found to be 135.9 ± 1.3 and 121.2 ±1.0 beats/min respectively with single and double operators; a significant (P < 0.01) reduction of 10.82 %. The corresponding work pulse (Δ HR) was 65.7 ± 0.9 and 51.5 ± 1.6 beats/min. The Δ HR was more than the allowable limit of 40 beats/min. HR work steadied after 6 minutes of threshing and there was complete recovery of HR after 6 minutes with double operators and 8 minutes with single operator. The increase in HR/kg of grain threshed was found to be 146.4 ± 4.4 and 76.0 ± 4.1 in case of single and double operators respectively; a significant reduction of 48 %. The workload decreased by 13.5 % with double operators but was still higher than the allowable limit of 35 % of VO2 max. The energy expenditure rate (ERR) was 18.9 ± 0.4 kJ/min with single operator and reduced to 16.6 ± 0.3 kJ/min with double operators. The total cardiac cost of work (TCCW) and physiological cost of work (PCW) reduced by 19.84 and 20 % with double operators. No significant variation of blood lactate accumulation between single and double operators was observed. The pedal force required was 232.3 ± 7.0 N and 199.7 ± 5.8 N in case of single operator and double operators respectively but was higher than the mean leg strength of the women of the eastern region of India. Higher pedal force application with double operators increased the number strokes/min (96/min) leading to a 51.15 % increase in output capacity of the thresher per hour per person. An increase of length of the pedal by 2 cm was suggested to reduce the force requirement. The length of the threshing drum can be reduced from 60.5 cm to 40 cm to be used by single operator or it can be increased to 75 cm to comfortably accommodate two persons.e 0.009167 and 0.776132, respectively