High sensitivity refractive index sensor based on simple diffraction from phase grating

We present a technique for refractive index sensing using a phase grating structure. A grating under normal incidence can be designed such that the 1st order diffracted light travels at a diffraction angle of 90o with respect to the 0th order. The diffracted light which is along the direction of periodicity can further get diffracted from the grating and interfere with the 0th order light. Under this condition, the π phase difference that arises between the two interfering beams results in a transmission dip. We can tune this dip wavelength for senor applications, based on the grating equation. Both simulation and experimental data are presented in the paper which shows good agreement with each other

Responsible Beverage Service Practices: Comparison between India and Australia

Sale and consumption of alcoholic beverages have been rising globally. This is making the alcohol industry worth over $1344 billion today. This rise in alcohol consumption has not been without its gray shades in the form of alcohol abuse, alcohol-related crimes, accidents and deaths. This paper studies and compares the Responsible Beverage Service practices between India and Australia to understand its scope and impact. The study draws upon review and analysis of research and data from literature and alcohol policies of the two countries. The study reveals the similarities and differences in the approach towards Responsible Beverage Service between these two countries and suggests methods to strengthen this practice in India

Adoption of RRII 400 series rubber clones by rubber small growers

The paper examines the response of small growers to the recommendation of multi-clonal planting in the context of release of RRII 400 series clones for commercial cultivation, since 2005. The data pertaining to 56080.6 ha under 130658 RPD permits, which availed subsidy from the Rubber Board during the seven year period from 2004 to 2010, were gathered from 26 Regional Offices of the Rubber Board located in the traditional rubber growing regions. The study revealed that the adoption had been characterised by the mono-clonal status (95.1%) of RRII 105 till the year 2004. However, the share of RRII 105 declined to 55.7 per cent in 2010. Conversely, share of RRII 400 series clones increased from 1.0 per cent in 2004 to 28 per cent in 2010 in the total planted area. But trends in adoption of new clones did not exhibit a consistent pattern across size-classes and regions during the post-release phase. It is in sharp contrast to the experience of RRII 105 since its release in 1980. Adoption of multi-clonal planting was only 2.6 per cent in 2004 which increased to more than 15 per cent in 2010. Multi-clonal planting was positively associated with the size of holdings during the period under review. But the strength of this relationship has been dependent on region-specific factors. Therefore, the study brings out the need for evolving a long term policy of region-specific clone recommendations based on life-cycle commercial yield performance

Trends in adoption of planting density in rubber smallholdings in the traditional regions of India

The analysis of planting density of rubber in small holdings for the period 2004-2010 indicated multifaceted features over time. In the traditional belt, except in North Kerala, the planting density of new planting was higher than that of replanting. After the release of RRII 400 series in the year 2005, significantly higher planting density was adopted for it in South Kerala. In all other regions, no significant difference in planting density was noticed between RRII 105 and RRII 400 series in the case of new planting, but higher density was adopted for replanting of RRII 105. An inverse relationship was observed between the size of holdings and planting density

Magnetic Nanoparticle-Based Nano-Grating Guided-Mode Resonance Biosensors

Biomolecular detection systems based on monitoring changes in the refractive indices of functionalized surfaces are promising for applications as chemical and biological sensors. Here, we describe the design and figures of merit of our refractive index-based guided-mode resonance (GR) biosensor consisting of thin film silicon nitride sub-wavelength nano-gratings. The sensitivity of our nano-grating GR sensor was experimentally determined to be 59.3 nm per refractive index unit. We describe how the wavelength for maximum intensity of diffraction (peak wavelength) of nano-gratings was affected when functionalized magnetic nanoparticles (MNPs) were attached onto GR sensor surfaces. Moreover, we demonstrate with avidin-biotin model experiments that attaching MNPs to sensor surfaces enhances the dynamic range of detection of the GR system detection. The peak wavelength value (PWV) shifted by 0.35 nm in the case of avidin with a concentration of avidin 400 nmol/L immobilized on the sensor surface. In contrast, we achieved a 1.41 nm PWV shift after adding 5% MNPs to the solution of avidin. Not only did the MNPs enhance the dynamic range of detection, but also magnetically induced interaction of avidin-biotin significantly reduced the detection time

Seasonal changes in xylem sap flow rate in mature rubber plants

The rate of flow of xylem sap of mature rubber tree was recorded round the clock continuously for two years using a Granier type thermal dissipation probe (TDP). The measurements were made on 19 year old trees of the clones, RRII 5 and PR 255 with a mean girth of 78 and 82 cm, respectively at 150 cm above bud union. Overall, the average rate of water mining by a tree was to the tune of 22 3 L day-1. The diurnal and seasonal differences in the sap flow rate were very evident which responded to the ambient weather conditions such as intensity of sunlight, temperature, rainfall etc. In the morning hours, as the sunlight intensity increased there was a corresponding sharp increase in sap flow rate which attained maximum level around mid-day. In the evening, as the light intensity declined, the sap flow rate also declined. The maximum rate of sap flow per day was recorded in December and the minimum in February coinciding with complete defoliation of the canopy. Taking a mean water consumption of 22 L tree-1day-1 and assuming there are 400 trees ha-1, the water consumption works out to be in the range of 1-2 mm day-1. This is significantly lesser than the potential evapo-transpiration (ET) of an open field in this traditional region. Taking the long-term average rain fall in the region (3000 mm year-1), it can be seen that the water loss due to transpiration (T) by the trees amounted only to 11 per cent of the annual rainfall

Transmission structured illumination microscopy with tunable frequency illumination using tilt mirror assembly

We present experimental demonstration of tilt-mirror assisted transmission structured illumination microscopy (tSIM) that offers a large field of view super resolution imaging. An assembly of custom-designed tilt-mirrors are employed as the illumination module where the sample is excited with the interference of two beams reflected from the opposite pair of mirror facets. Tunable frequency structured patterns are generated by changing the mirror-tilt angle and the hexagonal-symmetric arrangement is considered for the isotropic resolution in three orientations. Utilizing high numerical aperture (NA) objective in standard SIM provides super-resolution compromising with the field-of-view (FOV). Employing low NA (20X/0.4) objective lens detection, we experimentally demonstrate ∼ (0.56 mm× 0.35 mm) size single FOV image with ∼ 1.7- and ∼ 2.4-fold resolution improvement (exploiting various illumination by tuning tilt-mirrors) over the diffraction limit. The results are verified both for the fluorescent beads as well as biological samples. The tSIM geometry decouples the illumination and the collection light paths consequently enabling free change of the imaging objective lens without influencing the spatial frequency of the illumination pattern that are defined by the tilt-mirrors. The large and scalable FOV supported by tSIM will find usage for applications where scanning large areas are necessary as in pathology and applications where images must be correlated both in space and time