Rapid-purification protocols for optical homodyning

We present a number of rapid-purification feedback protocols for optical homodyne detection of a single optical qubit. We derive first a protocol that speeds up the rate of increase of the average purity of the system, and find that like the equivalent protocol for a non-disspative measurement, this generates a deterministic evolution for the purity in the limit of strong feedback. We also consider two analogues of the Wiseman-Ralph rapid-purification protocol in this setting, and show that like that protocol they speed up the average time taken to reach a fixed level of purity. We also examine how the performance of these algorithms changes with detection efficiency, being an important practical consideration.Comment: 6 pages, revtex4, 3 eps figure

Thermodynamic Model of a Very High Efficiency Power Plant Based on a Biomass Gasifier, SOFCs, and a Gas Turbine

Thermodynamic calculations with a power plant based on a biomass gasifier, SOFCs and a gas turbine are presented. The SOFC anode off-gas which mainly consists of steam and carbon dioxides used as a gasifying agent leading to an allothermal gasification process for which heat is required. Implementation of heat pipes between the SOFC and the gasifier using two SOFC stacks and intercooling the fuel and the cathode streams in between them has shown to be a solution on one hand to drive the allothermal gasification process and on the other hand to cool down the SOFC. It is seen that this helps to reduce the exergy losses in the system significantly. With such a system, electrical efficiency around 73% is shown as achievable

Assessment on the harnessing of the energy from the back pressure chamber of palm oil mill

Malaysia being the second largest palm oil producer produced bio mass as a by-product. Essentially the bio mass is used as energy resource in the palm industry to cater for power requirements through co-generation process. However part of the unused steam is let out to the atmosphere through the back pressure chamber. Most of the mills are in the position to generate more power and supply electricity to nearby residential areas. In some or in most of the cases the low pressure steam is let to atmosphere as the power produced is normally more than sufficient for use in the palm oil mill. The assessment on the feasibility of recovering the let out steam through a small turbine generator set is presented in this paper. Also the choice on the optimal valve size used in the expansion of the turbine is found to influence the power production. The estimation on the available energy through this is about 35% of the main plant used energy for the optimal valve sizing of 3 inch. A numerical design analysis on the back pressure chamber energy is developed and the computations on the energy are presented

Effect of H₂S and HCl contaminants on nickel and ceria pattern anode solid oxide fuel cells

In this study, with the motivation of elucidating the effect of H2S and HCl on solid oxide fuel cell anodes, nickel and ceria pattern anodes are prepared on yttrium-stabilized zirconia electrolyte, and the effect of H2S and HCl on their performance is tested using electrochemical impedance spectroscopy. However, it has been found that while H2S adversely impacts both nickel and ceria, the poisoning caused is reversible for nickel and only partially reversible for ceria. Poisoning kinetics are similar and fast for both materials, while recovery kinetics are slower for ceria than nickel. High sulfur coverage is the rate-limiting factor inferred from the elementary kinetic modeling. Unlike H2S, the presence of HCl appeared to be favorable for electrochemical oxidation as the polarization resistance of both pattern electrode cells decreased upon feeding HCl contaminated hydrogen gas. Similar behavior has not been reported previously, and the conclusion regarding underlying mechanisms requires further investigation

Review on the grand challenges for engineering: a framework for the future

The paper presents the thrust research outcomes to solve the engineering grand challenges for the 21st century. Fourteen grand challenges were addressed and introduced in 2008 as a framework that capture the most immediate solution engineers need to address within the 21st century by the National Academy of Engineers. The grand challengesare groupedas 14 grand challenges in order to create focus groups. The fourteen challenges are comprehensively presented and a framework classification to identify our research directions towards societal purpose and value is presented

Quantum Algebras Associated With Bell States

The antisymmetric solution of the braided Yang--Baxter equation called the Bell matrix becomes interesting in quantum information theory because it can generate all Bell states from product states. In this paper, we study the quantum algebra through the FRT construction of the Bell matrix. In its four dimensional representations via the coproduct of its two dimensional representations, we find algebraic structures including a composition series and a direct sum of its two dimensional representations to characterize this quantum algebra. We also present the quantum algebra using the FRT construction of Yang--Baxterization of the Bell matrix.Comment: v1: 15 pages, 2 figures, latex; v2: 18 pages, 2 figures, latex, references and notes adde

Nonlinear Coherent Modes of Trapped Bose-Einstein Condensates

Nonlinear coherent modes are the collective states of trapped Bose atoms, corresponding to different energy levels. These modes can be created starting from the ground state condensate that can be excited by means of a resonant alternating field. A thorough theory for the resonant excitation of the coherent modes is presented. The necessary and sufficient conditions for the feasibility of this process are found. Temporal behaviour of fractional populations and of relative phases exhibits dynamic critical phenomena on a critical line of the parametric manifold. The origin of these critical phenomena is elucidated by analyzing the structure of the phase space. An atomic cloud, containing the coherent modes, possesses several interesting features, such as interference patterns, interference current, spin squeezing, and massive entanglement. The developed theory suggests a generalization of resonant effects in optics to nonlinear systems of Bose-condensed atoms.Comment: 26 pages, Revtex, no figure

Effect of different biofloc system on water quality, biofloc composition and growth performance in Litopenaeus vannamei (Boone, 1931)

The experiment was conducted with three biofloc treatments and one control in triplicate in 500 L capacity indoor tanks. Biofloc tanks, filled with 350 L of water, were fed with sugarcane molasses (BFTS), tapioca flour (BFTT), wheat flour (BFTW) and clean water as control without biofloc and allowed to stand for 30 days. The postlarvae of Litopenaeus vannamei (Boone, 1931) with an Average body weight of 0.15 � 0.02 g were stocked at the rate of 130 PL m �2 and cultured for a period of 60 days fed with pelleted feed at the rate of 1.5% of biomass. The total suspended solids (TSS) level was maintained at around 500 mg L �1 in BFT tanks. The addition of carbohydrate significantly reduced the total ammonia- N (TAN), nitrite-N and nitrate-N in water and it significantly increased the total heterotrophic bacteria (THB) population in the biofloc treatments. There was a significant difference in the final average body weight (8.49 � 0.09 g) in the wheat flour treatment (BFTW) than those treatment and control group of the shrimp. Survival of the shrimps was not affected by the treatments and ranged between 82.02% and 90.3%. The proximate and chemical composition of biofloc and proximate composition of the shrimp was significantly different between the biofloc treatments and control. Tintinids, ciliates, copepods, cyanobacteria and nematodes were identified in all the biofloc treatments, nematodes being the most dominant group of organisms in the biofloc. It could be concluded that the use of wheat flour (BFTW) effectively enhanced the biofloc production and contributed towards better water quality which resulted in higher production of shrimp