Constraints in dry chilli cultivation practices and mechanization of harvesting in Southern India

Dry chilli production in India condition faces many challenges apart from adverse weather conditions, labor-intensive production practices and higher overall production costs are limiting profitable dry chilli cultivation. Therefore, a study was carried to know the key constraints in current chilli production practices in eight major production districts of three states. A systematic research and development approach is essential to know the range of constraints and farmers preferences over technological options for field operations. The harvesting operation alone demands 43% of labour 360.5 man-days/ha. So, red chilli harvesting mechanization is a definite immediate requirement to reduce labour input. Farmers (47%) prefer small size self-propelled chilli harvester over tractor operated equipment. In the production catchments, farmer also inferred to change the cultivation practices to mechanize chilli production operations, but 18% of farmers hesitant to adopt one-timeharvesting chilli varieties due to suspicion about the yield potentials

Dye molecules in electrolytes: new approach for suppression of dye-desorption in dye-sensitized solar cells

The widespread commercialization of dye-sensitized solar cells remains limited because of the poor long-term stability. We report on the influence of dye-molecules added in liquid electrolyte on long-term stability of dye-sensitized solar cells. Dye-desorption from the TiO2 surface during long-term cycling is one of the decisive factors that degrade photocurrent densities of devices which in turn determine the efficiencies of the devices. For the first time, desorption of dye from the TiO2 surface could be suppressed by controlling thermodynamic equilibrium; by addition of dye molecules in the electrolyte. The dye molecules in the electrolyte can suppress the driving forces for the adsorbed dye molecules to be desorbed from TiO2 nanoparticles. As a result, highly enhanced device stabilities were achieved due to the reduction of dye-desorption although there was a little decrease in the initial efficiencies.open4

DNA barcoding and surveillance sampling strategies for Culicoides biting midges (Diptera: Ceratopogonidae) in southern India

Background: Culicoides spp. biting midges transmit bluetongue virus (BTV), the aetiological agent of bluetongue (BT), an economically important disease of ruminants. In southern India, hyperendemic outbreaks of BT exert high cost to subsistence farmers in the region, impacting on sheep production. Effective Culicoides spp. monitoring methods coupled with accurate species identification can accelerate responses for minimising BT outbreaks. Here, we assessed the utility of sampling methods and DNA barcoding for detection and identification of Culicoides spp. in southern India, in order to provide an informed basis for future monitoring of their populations in the region. Methods: Culicoides spp. collected from Tamil Nadu and Karnataka were used to construct a framework for future morphological identification in surveillance, based on sequence comparison of the DNA barcode region of the mitochondrial cytochrome c oxidase I (COI) gene and achieving quality standards defined by the Barcode of Life initiative. Pairwise catches of Culicoides spp. were compared in diversity and abundance between green (570 nm) and ultraviolet (UV) (390 nm) light emitting diode (LED) suction traps at a single site in Chennai, Tamil Nadu over 20 nights of sampling in November 2013. Results: DNA barcode sequences of Culicoides spp. were mostly congruent both with existing DNA barcode data from other countries and with morphological identification of major vector species. However, sequence differences symptomatic of cryptic species diversity were present in some groups which require further investigation. While the diversity of species collected by the UV LED Center for Disease Control (CDC) trap did not significantly vary from that collected by the green LED CDC trap, the UV CDC significantly outperformed the green LED CDC trap with regard to the number of Culicoides individuals collected. Conclusions: Morphological identification of the majority of potential vector species of Culicoides spp. samples within southern India appears relatively robust; however, potential cryptic species diversity was present in some groups requiring further investigation. The UV LED CDC trap is recommended for surveillance of Culicoides in southern India

Investigation of a new bis(carboxylate)triazole-based anchoring ligand for dye-sensitised solar cell chromophore complexes

A novel anchoring ligand for dye-sensitised solar cell chromophoric complexes, 1-(2,2’-bipyrid-4-yl)-1,2,3-triazole-4,5-dicarboxylic acid (dctzbpy), is described. The new dye complexes [Ru(bpy)2(dctzbpy)][PF6]2 (AS16), [Ir(ppy)2(dctzbpy)][PF6] (AS17) and [Re(dctzbpy)(CO)3Cl] (AS18) were prepared in a two stage procedure with intermediate isolation of their diester analogues, AS16-Et2, AS17-Et2 and AS18-Et2 respectively. Electrochemical analysis of AS16-Et2, AS17-Et2 and AS18-Et2 reveal reduction potentials in the range -1.50 to -1.59 V (vs Fc+/Fc) which is cathodically shifted with respect to that of the model complex [Ru(bpy)2(dcbH2)]2+ (1) (Ered = -1.34 V, dcbH2 = 2,2’-bipyridyl-4,4’dicarboxylic acid). This therefore demonstrates that the LUMO of the complex is correctly positioned for favourable electron transfer into the TiO2 conduction band upon photoexcitation. The higher energy LUMOs for AS16 to AS18 and a larger HOMO-LUMO gap result in blue-shifted absorption spectra and hence reduced light harvesting efficiency relative to their dcbH2 analogues. Preliminary tests on TiO2 n-type and NiO p-type DSSCs have been carried out. In the cases of the Ir(III) and Re(I) based dyes AS17 and AS18 these show inferior performance to their dcbH2 analogues. However, the Ru(II) dye AS16 (η = 0.61 %) exhibits significantly greater efficiency than 1 (η = 0.1 %). In a p-type cell AS16 shows the highest photovoltaic efficiency (η = 0.028 %), almost three times that of cells incorporating the benchmark dye coumarin C343

Quasi-static response and multi-objective crashworthiness optimization of oblong tube under lateral loading

University of Alepp

Carbon Nanotube Solar Cells

We present proof-of-concept all-carbon solar cells. They are made of a photoactive side of predominantly semiconducting nanotubes for photoconversion and a counter electrode made of a natural mixture of carbon nanotubes or graphite, connected by a liquid electrolyte through a redox reaction. The cells do not require rare source materials such as In or Pt, nor high-grade semiconductor processing equipment, do not rely on dye for photoconversion and therefore do not bleach, and are easy to fabricate using a spray-paint technique. We observe that cells with a lower concentration of carbon nanotubes on the active semiconducting electrode perform better than cells with a higher concentration of nanotubes. This effect is contrary to the expectation that a larger number of nanotubes would lead to more photoconversion and therefore more power generation. We attribute this to the presence of metallic nanotubes that provide a short for photo-excited electrons, bypassing the load. We demonstrate optimization strategies that improve cell efficiency by orders of magnitude. Once it is possible to make semiconducting-only carbon nanotube films, that may provide the greatest efficiency improvement

What difference does a thiophene make? Evaluation of a 4,4′-bis(thiophene) functionalised 2,2′-bipyridyl copper(I) complex in a dye-sensitized solar cell

AbstractThe synthesis of a 4,4′-bis(2-thienyl-5-carboxylic acid) functionalised 2,2′-bipyridine ligand and corresponding copper(I) complex is described and its application in a dye-sensitized solar cell (DSSC) is studied. The positioning of the thiophene groups appears favourable from DFT analysis and a best efficiency of 1.41% was obtained with this dye, for a 0.3 cm2 cell area DSSC. Two absorbance bands are observed in the electronic absorption spectrum of the copper(I) complex at 316 nm and 506 nm, with ε values of 50,000 M−1 cm−1 and 9030 M−1 cm−1, respectively. Cyclic voltammetry and electrochemical impedance spectroscopy are also used to provide a detailed analysis of the dye and assess its functionality in a DSSC