Quantum electrodynamical theory of high-efficiency excitation energy transfer in laser-driven nanostructure systems

A fundamental theory is developed for describing laser-driven resonance energy transfer (RET) in dimensionally constrained nanostructureswithin the framework of quantum electrodynamics. The process of RET communicates electronic excitation between suitably disposed emitter and detector particles in close proximity, activated by the initial excitation of the emitter. Here, we demonstrate that the transfer rate can be significantly increased by propagation of an auxiliary laser beam through a pair of nanostructure particles. This is due to the higher order perturbative contribution to the F¨orster-type RET, in which laser field is applied to stimulate the energy transfer process. We construct a detailed picture of how excitation energy transfer is affected by an off-resonant radiation field, which includes the derivation of second and fourth order quantum amplitudes. The analysis delivers detailed results for the dependence of the transfer rates on orientational, distance, and laser intensity factor, providing a comprehensive fundamental understanding of laser-driven RET in nanostructures. The results of the derivations demonstrate that the geometry of the system exercises considerable control over the laser-assisted RET mechanism. Thus, under favorable conformational conditions and relative spacing of donor-acceptor nanostructures, the effect of the auxiliary laser beam is shown to produce up to 70% enhancement in the energy migration rate. This degree of control allows optical switching applications to be identified

Gender Inequality in Digital Transformation: Evidence from Business Process Management Industry in Sri Lanka

This research examines whether gender inequality exists in Leadership Style, Organizational Culture, and Digital Competence of digital transformation of the Business Process Management (BPM) industry. Data were collected from 507 employees of 40 Sri Lankan BPM companies through a web-based survey. Mann-Whitney U test with descriptive statistics provided evidence to strengthen the findings. The findings confirmed that gender inequality exists in Leadership Style, Organizational Culture, and Digital Competence of digital transformation in the BPM industry in Sri Lanka. This research contributes to "Acker's Theory of Gendered Organizations" by identifying areas that reproduce gender inequality in the new digital economy workplace. This study recommends controlling if not eradicating the gender inequality through proper Human Resource (HR) policies and procedures since it may hinder organizational performance. Digital workplace will improve employee retention, satisfaction, and productivity. Keywords: Business Process Management, Gender Inequality, Leadership Style, Organizational Culture, Digital Competenc

Hernia into the umbilical cord with incarceration of liver and gall bladder in a newborn

AbstractIncarceration of liver tissue in a hernia of the umbilical cord is a rare occurrence. An incarceration of the gall bladder is even rarer. We report such a case in a newborn that had incarceration of both liver and gall bladder in to the umbilical cord

Yield, Feeding Value and Ensiling Characteristics of Clone-13 (\u3ci\u3ePennisetum purpureum\u3c/i\u3e)

A study was carried out to find out the effect of frequency of defoliation on yield and feeding value of clone-13 (Pennisetum purpureum) in Sri Lanka. Three frequency of harvesting, namely 45, 60 and 75 days were used and, fresh yield per plot was measured. Sub samples were taken for dry matter determination and proximate analysis. According to results, frequency of harvesting of 60 days can be recommended for clone-13 under no fertilizer regime. In addition, effect of growth stage on ensiling characteristics of clone-13 was also studied. Clone-13 was harvested at 45, 60, 75 or 90 days and, ensiled alone or with 5% coconut (Cocos nucifera L.) scrapings or 5% rice (Oriza sativa) bran in laboratory silos. Therefore, altogether 12 treatments were used in the study with 5 replicates. Silos were opened after 6 weeks and, physical and ensiling characteristics were studied. Physical characteristics of silage were satisfactory and had a yellowish brown colour, pleasant aroma and a moist texture. Highest volatile fatty acids and crude protein contents were observed with 45 days old grass silage whereas lowest in 90 days old grass silage. Addition of rice bran and coconut scrapings improved the fermentation characteristics of silage compared to no additives

Controlling resonance energy transfer in nanostructure emitters by positioning near a mirror

The ability to control light-matter interactions in quantum objects opens up many avenues for new applications. We look at this issue within a fully quantized framework using a fundamental theory to describe mirror-assisted resonance energy transfer (RET) in nanostructures. The process of RET communicates electronic excitation between suitably disposed donor and acceptor particles in close proximity, activated by the initial excitation of the donor. Here, we demonstrate that the energy transfer rate can be significantly controlled by careful positioning of the RET emitters near a mirror. The results deliver equations that elicit new insights into the associated modification of virtual photon behavior, based on the quantum nature of light. In particular, our results indicate that energy transfer efficiency in nanostructures can be explicitly expedited or suppressed by a suitably positioned neighboring mirror, depending on the relative spacing and the dimensionality of the nanostructure. Interestingly, the resonance energy transfer between emitters is observed to “switch off” abruptly under suitable conditions of the RET system. This allows one to quantitatively control RET systems in a new way

Silage Characteristics of Sugarcane (\u3cem\u3eSacchrum officinarum\u3c/em\u3e) Tops in Sri Lanka

Sugarcane tops (SCTs) is generally known to be a major byproduct of sugarcane industry which is currently not utilized in a profitable manner and it is widely available at low cost particularly during the dry period in Sri Lanka when the forage are scarce for feeding of ruminants. Usually, the residue after sugarcane harvesting contains dry leaves, fresh leaves and growing point of the stalk. It increases drying of leaves in the field within 2 to 3 days after harvesting due to dry weather conditions prevailing in the harvesting period and much of the tops are burned and wasted in the field. Therefore, it is difficult to use tops as feed unless they are preserved. Silage making is a good preservation technique which can be used under this condition. Therefore, the objective of this study was to compare the ensiling characteristics and nutritive value of SCTs or Guinea (Panicum maximum) ‘A’ grass with different additives

High Efficient Dye-Sensitized Solar Cells Based on Synthesized SnO 2

In this study, SnO2 semiconductor nanoparticles were synthesized for DSC applications via acid route using tin(ii) chloride as a starting material and hydrothermal method through the use of tin(iv) chloride. Powder X-ray diffraction studies confirmed the formation of the rutile phase of SnO2 with nanoranged particle sizes. A quasi-solid-state electrolyte was employed instead of a conventional liquid electrolyte in order to overcome the practical limitations such as electrolyte leakage, solvent evaporation, and sealing imperfections associated with liquid electrolytes. The gel electrolytes were prepared incorporating lithium iodide (LiI) and tetrapropylammonium iodide (Pr4N+I−) salts, separately, into the mixture which contains polyacrylonitrile as a polymer, propylene carbonate and ethylene carbonate as plasticizers, iodide/triiodide as the redox couple, acetonitrile as the solvent, and 4-tertiary butylpyridine as an electrolyte additive. In order to overcome the recombination problem associated with the SnO2 due to its higher electron mobility, ultrathin layer of CaCO3 coating was used to cover the surface recombination sites of SnO2 nanoparticles. Maximum energy conversion efficiency of 5.04% is obtained for the device containing gel electrolyte incorporating LiI as the salt. For the same gel electrolyte, the ionic conductivity and the diffusion coefficient of the triiodide ions are 4.70 × 10−3 S cm−1 and 4.31 × 10−7 cm2 s−1, respectively

Enhancing Performance of SnO 2

Although liquid electrolyte based dye-sensitized solar cells (DSCs) have shown higher photovoltaic performance in their class, they still suffer from some practical limitations such as solvent evaporation, leakage, and sealing imperfections. These problems can be circumvented to a certain extent by replacing the liquid electrolytes with quasi-solid-state electrolytes. Even though SnO2 shows high election mobility when compared to the semiconductor material commonly used in DSCs, the cell performance of SnO2-based DSCs is considerably low due to high electron recombination. This recombination effect can be reduced through the use of ultrathin coating layer of ZnO on SnO2 nanoparticles surface. ZnO-based DSCs also showed lower performance due to its amphoteric nature which help dissolve in slightly acidic dye solution. In this study, the effect of the composite SnO2/ZnO system was investigated. SnO2/ZnO composite DSCs showed 100% and 38% increase of efficiency compared to the pure SnO2-based and ZnO-based devices, respectively, with the gel electrolyte consisting of LiI salt

Surface plasmon subwavelength optics

Abstract: The conventional analysis of surface plasmon modes on dielectric-metal interfaces requires clearly defining the permittivity discontinuity at the interface. A pivotal assumption of such an analysis is that the formation of the dielectric-metal interface does not change the material properties and the materials forming the interface have identical permittivities before and after the formation of the interface. However, this assumption breaks down if an interface is made between a metal and a semiconductor which is commonly known as a Schottky junction. Under certain conditions, such an interface can sustain a surface plasmon polariton (SPP) mode. It is also possible to change the properties of the media surrounding the Schottky junction interface by applying an external potential difference across the junction. Central to the understanding of the SPP mode behaviour in such a complex morphological interface is the dispersion relation which defines the feasible SPP modes and their characteristics. Here, we carry out a detailed analysis to derive an analytical expression for the dispersion relation for a Schottky junction. Our analysis takes into account the space charge layer formed due to the charge distribution across the Schottky junction and resulting new boundary conditions