145 research outputs found
Hybrid solar cell with TiO2 film: BBOT polymer and copper phthalocyanine as sensitizer
An organic-inorganic hybrid solar cell was fabricated using Titanium dioxide (TiO2): 2,5-bis(5-tert-butyl-2-benzoxazolyl) thiophene (BBOT) film and Copper Phthalocyanine (CuPc) as a sensitizer. BBOT was used in photodetector in other reported research works, but as per best of our knowledge, it was not implemented in solar cells till date. The blend of TiO2: BBOT blend was used to fabricate the film on ITO-coated glass and further a thin layer of CuPc was coated on the film. This was acted as photoanode and another ITO coated glass with a platinum coating was used as a counter electrode (cathode). An optimal blend of acetonitrile (solvent) (50-100%), 1,3-dimethylimidazolium iodide (10-25%), iodine (2.5-10%) and lithium iodide, pyridine derivative and thiocyanate was used as electrolytes in the hybrid solar cell. The different structural, optical and electrical characteristics were measured. The Hybrid solar cell showed a maximum conversion efficiency of 6.51%
Voltage Stability Prediction on Power Networks using Artificial Neural Networks
The objective of this paper is to predict the secure or the insecure state of the power system network using a hybrid technique which is a combination of Artificial Neural Network (ANN) and voltage stability indexes. Voltage collapse or an uncontrollable drop in voltage occurs in a system when there is a change in the condition of the system or a system is overloaded. A Transference Index (TI) which acts as a voltage stability indicator has been formulated from the equivalent two-bus network of a multi-bus power system network, which has been tested on a standard IEEE 30-bus system and the result is validated with a standard Fast Voltage Stability Index (FVSI). FACTS devices in the critical bus have been considered for the improvement of the voltage stability of the system. An ANN based supervised learning algorithm has been conferred in this paper alongside Contingency Analysis (CA) for the prediction of voltage security in an IEEE 30 - bus power system network.
Geotechnical study of behaviour of high concentration settled ash slurry
Electric power generation in India increases to several times in last fifty years the major chunk of power came from the coal based thermal power industries by burning of coal. As result huge quantities of coal ash is produced from the thermal industries. Only little percentage is used for the various productions like cement, bricks, mass concreting and road construction. Rest major portion are lying as a land fill called ash ponds being discharged in the slurry. Traditional ash slurry disposal system like lean slurry disposal pose lot many problems regarding to stability seepage etc. endangering to the stability of thermal power plant. Recently high concentrated ash disposal (HCSD) system is being introduced in some of the industries to overcome those problems. The behaviour of this HCSD disposal system and a comparison with lean slurry will enable a detailed insight to the thermal power industries. The aim of the project is to geotechnical study on the behaviour of high concentrated ash slurry. From Vedanta Jharsuguda Aluminium plant disturbed and undisturbed sample are collected, field test are also conducted. Experiment such as Modified Proctor test, Standard Proctor Test for determining MDD and OMC, Specific Gravity Test, in-situ density Test, permeability Test, along with Variations of Bulk density, water content and dry density with time at field are done in order to determine the geo-engineering properties high concentrated fly ash slurry
Coherent Control of Low Anharmonicity Systems for Superconducting Quantum Computing
This dissertation describes research to coherently control quantum states of superconducting devices. In the first project, the state of an 8 GHz 3D superconducting Al cavity at 20mK was manipulated to add a quantum of excitation. Preparing a harmonic resonator in a state with a well-defined number of excitations (Fock states) is not possible using one external classical drive. I generated Fock states by transferring a single excitation from a 5.5 GHz transmon qubit to a cavity using Stimulated Raman Adiabatic Passage (STIRAP). I also extended the STIRAP technique to put the cavity in higher Fock states, superpositions of Fock states, and Bell states between the qubit and the cavity. Master-equation simulations of the system’s density matrix were in good agreement with the data, and I obtained estimated fidelities of 89%, 68% and 43% for the first three Fock states, respectively.
The second project involved implementing an entangling gate between two Al/AlOx/Al transmon qubits that were mounted in an Al cavity and cooled to 20mK. Pertinent system frequencies were as follows: one qubit was at 6.0 GHz, the other qubit at 6.8 GHz, the cavity at 7.7 GHz, and the qubit-qubit dispersive shift was -1MHz. By applying a specially-shaped pulse of duration tg = 907ns, I implemented a generalized CNOT gate using an all-microwave technique known as Speeding up Waveforms by Inducing Phases to Harmful Transitions (SWIPHT). Using quantum process tomography, I found that the gate fidelity was 80%–82%, close to the 87% fidelity expected from decoherence in the transmons during the gate time. Details of the device fabrication, device characterization, measurement techniques, and extensive modeling of device behavior are presented, along with chi-matrix characterization of single-qubit gates and SWIPHT gates
Assessment of Voltage Stability Using Network Equivalent
In this paper a fast system voltage stability index (FSVSI) has been proposed to assess overall system voltage stability of a multi-bus power system at a particular operating point using the concept of two bus network equivalent. A universal direct voltage stability index has also been explored to assess local (DVSI) as well as overall system voltage stability (DSVSI). An index called system transmission quality factor (STQF) has been developed to assess the power transmission quality of the overall system in the context of voltage stability. Two FACTS controllers, TCSC and STATCOM have also been incorporated in the present study to observe their effectiveness to ensure voltage stabilty. STATCOM has been found to be superior in order to improve voltage stability of power system as compared to TCSC. The developed concept has been validated using practical India Easten Grid (WBSEB system) and it has a high potential of on-line application
Communication of cancer screening results by letter, telephone or in person: A mixed methods systematic review of the effect on attendee anxiety, understanding and preferences
Attending and receiving a result from screening can be an anxious process. Using an appropriate method to deliver screening results could improve communication and reduce negative outcomes for screening attendees. Screening programmes are increasingly communicating results by letter or telephone rather than in-person. We investigated the impact of communication methods on attendees.
We systematically reviewed the literature on the communication methods used to deliver results in cancer screening programmes for women, focusing on screening attendee anxiety, understanding of results and preferences for results communication. We included qualitative and quantitative research. We searched MEDLINE, PsycINFO, CINAHL, Cochrane Library and Embase. Results were analysed using framework synthesis. 10,558 papers were identified with seven studies meeting the inclusion criteria.
Several key ideas emerged from the synthesis including speed, accuracy of results, visual support, ability to ask questions, privacy of results location and managing expectations.
Verbal communication methods (telephone and in-person) were preferred and facilitated greater understanding than written methods, although there was considerable variability in attendee preferences. Findings for anxiety were mixed, with no clear consensus on which method of communication might minimise attendee anxiety.
The low number of identified studies and generally low quality evidence suggest we do not know the most appropriate communication methods in the delivery of cancer screening results. More research is needed to directly compare methods of results communication, focusing on what impact each method may have on screening attendees
Suitability Evaluation of Three Tropical Pasture Species (Mulato II, Gatton Panic, and Rhodes Grass) for Cultivation under a Subtropical Climate of Australia
Exploring improved tropical forages is considered to be an important approach in delivering quality and consistent feed options for dairy cattle in tropical and subtropical regions. The present study aimed to study the suitability of three improved tropical grasses, Chloris gayana ‘Rhodes grass cv. Reclaimer’ (RR), Megathyrsus maximus ‘Gatton Panic’ (GP), and Brachiaria ruziziensis x B. decumbens x B. brizantha ‘Brachiaria Mulato II’ (BM) evaluating their carbon assimilation, canopy structure, herbage plant–part accumulation and quality parameters under irrigated conditions. An experiment was conducted at Gatton Research Dairy (27°54′ S, 152°33′ E, 89 m asl) Queensland, Australia, which has a predominantly subtropical climate. Photosynthesis biochemistry, canopy structure, herbage accumulation, plant part composition, and nutritive value were evaluated. Photosynthesis biochemistry differed between pasture species. Efficiency of CO2 assimilation was highest for GP and quantum efficiency was highest for BM. Pasture canopy structure was significantly affected by an interaction between pasture species and harvest. Forage biomass accumulation was highest in GP, while BM produced more leaf and less stem compared to both GP and RR. A greater leafy stratum and lower stemmy stratum depth were observed in the vertical sward structure of BM. Brachiaria Mulato II showed greater carbon partitioning to leaves, leaf: stem ratio, canopy, and leaf bulk density. It also demonstrated greater nutritive value (Total digestible nutrients (TDN), acid detergent fibre (ADF), neutral detergent fibre (NDF), neutral detergent insoluble protein (NDICP), Starch, nonfibre carbohydrates (NFC), metabolisable energy (ME), mineral profile (Mg, P, K, Fe, Zn) and dietary cation–anion difference (DCAD) for leaf, stem, and the whole plant. Greater quantum efficiency, leaf accumulation, and nutritive value of BM observed in the present study suggest BM as an attractive forage option for dairying that warrants further research in pasture-based systems in tropical and subtropical climates
Endless Dirac nodal lines and high mobility in kagome semimetal Ni3In2Se2 single crystal
Kagome-lattice crystal is crucial in quantum materials research, exhibiting
unique transport properties due to its rich band structure and the presence of
nodal lines and rings. Here, we investigate the electronic transport properties
and perform first-principles calculations for NiInSe kagome
topological semimetal. First-principle calculations indicate six endless Dirac
nodal lines and two nodal rings with a -Berry phase in the
NiInSe compound. The temperature-dependent resistivity is
dominated by two scattering mechanisms: - interband scattering occurs
below 50 K, while electron-phonon (-) scattering is observed above 50 K.
The magnetoresistance (MR) curve aligns with the theory of extended Kohler's
rule, suggesting multiple scattering origins and temperature-dependent carrier
densities. A maximum MR of 120\% at 2 K and 9 T, with a maximum estimated
mobility of approximately 3000 cmVs are observed. The Ni
atom's hole-like d and electron-like d orbitals
exhibit peaks and valleys, forming a local indirect-type band gap near the
Fermi level (E). This configuration enhances the motion of electrons and
holes, resulting in high mobility and relatively high magnetoresistance
Technical Efficiency for Tea Smallholder Farmers under UTZ Certification System in Sri Lanka: A Stochastic Frontier Approach
The study aimed to identify the determinants of the technical efficiency of Smallholder Tea Farmers (STFs) under UTZ certification system in Sri Lanka by employing stochastic production frontier using a sample survey of 75 STFs supported by the UTZ programme conducted between January and March in 2016. The results showed that a small number of STFs (11.8 percent) were over 90 percent efficient and the level of efficiency was found to be negatively related to coefficients of UTZ certified STFs and positively related to number of years with the same plants. The results further showed the labor and fertilizer were the significant factors that determine the tea production of STFs
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