Analytical error analysis of Clifford gates by the fault-path tracer method

We estimate the success probability of quantum protocols composed of Clifford operations in the presence of Pauli errors. Our method is derived from the fault-point formalism previously used to determine the success rate of low-distance error correction codes. Here we apply it to a wider range of quantum protocols and identify circuit structures that allow for efficient calculation of the exact success probability and even the final distribution of output states. As examples, we apply our method to the Bernstein–Vazirani algorithm and the Steane [[7,1,3]] quantum error correction code and compare the results to Monte Carlo simulations.     

Study of micro-structural,optical and electrical properties of TiO2 films obtained from micro-controller based SILAR method

The TiO₂ films were obtained from successive ion layer adsorption and reaction (SILAR) method. A micro-controller based SILAR unit was used to precisely monitor and control the deposition parameters. The films were uniform and free from physical defects such as pores and cracks. A maximum thickness of about 700?nm was achieved. The films were found to be polycrystalline without any texture or preferred orientations. The crystallite size of the films was found to increase with thickness while the micro strain and stress were found to reduce with the thickness. Post-deposition annealing was also found to produce the similar results. The films were found to possess an indirect bandgap of about 3?eV. Various technically important parameters such as root-mean-square micro strain, Urbach energy, chemical composition, carrier concentration, electrical resistivity etc. were determined. The effects of deposition parameters on the properties of the films is discussed in detail.     

Penetration enhancers and ocular bioadhesives: two new avenues for ophthalmic drug delivery

This review is focused on the two avenues of development that promise a major impact on future ocular drug therapeutics: bioadhesives, including hydrogels and other agents like carbopols, polyacrylic acids, chitosan, etc., and penetration enhancers, including different surfactants, calcium chelators, etc. The capacity of some polymers to adhere to the mucin coat covering the conjunctiva and the corneal surface of the eye forms the basis for ocular mucoadhesion. These systems markedly prolong the residence time of a drug in the conjunctival sac, since clearence is now controlled by the much slower rate of mucus turnover rather than the tear turnover rate. But improving the corneal drug retention alone is inadequate in bringing about a significant improvement of drug bioavailability. Another approach consists of transiently increasing the pentration characteristics of the cornea with appropriate substances, known as penetration enhancers or absorption promoters. The main aim of this article is to give an insight into the potential application of mucoadhesives and corneal penetration enhancers for the conception of innovative opthalmic delivery appraoches, to decrease the systemic side effects, and create a more focused effect, which may be achieved with lower doses of the drug. Ophthalmic formulations based on these mucoadhesives and penetration enhancers are simple to manufacture and exhibit an excellent tolerance when administered into the cornea. The use of the former considerably prolongs the corneal contact time and the use of the latter increases the rate and amount of drug transport. The various corneal epithelial barriers along with the major routes of transport of drugs are discussed. The article includes a list of the various substances in use or under investigation for the aforementioned properties, along with their mechanisms of action. A fair appraisal of the subject with regard to these two therapeutic approaches and any expected ill effects has been made.     

Gas permeation properties of polyamide membrane prepared by interfacial polymerization

Interfacial polymerization technique has been widely employed to prepare reverse osmosis (RO) and nanofiltration (NF) membranes. The present study explores the possibility of preparing a polyamide membrane by interfacial polymerization and its utilization for the separation of CO₂ and H₂S from CH₄. A novel ultraporous substrate of polysulfone (PSF) was prepared by phase inversion technique from a solution containing 18% PSF and 4% propionic acid in dimethyl formamide (DMF) solvent. Thin film composite (TFC) polyamide membrane was synthesized on PSF substrate from the reaction between meta-phenylene diamine in an aqueous media and isophthaloyl chloride in hexane. The membrane prepared was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) to study intermolecular interactions, crystallinity, thermal stability and surface morphology, respectively. Gas permeabilities of pure CO₂, H₂S, CH₄, O₂, and N₂ gases were measured using the indigenously built permeation cell incorporated into a high-pressure gas separation manifold. At the feed pressure of 1 MPa, the membrane exhibited permeances of 15.2 GPU for CO₂ and 51.6 GPU for H₂S with selectivities of 14.4 and 49.1 for CO₂/CH₄ and H₂S/CH₄ systems, respectively. The observed N₂ permeance of 0.95 GPU was close to that of CH_4. The corresponding O₂ permeance was 5.13 GPU with a reasonably high O₂/N₂ selectivity of 5.4. The effect of feed pressure on polyamide membrane performance was examined. Further, molecular dynamics (MD) simulations were employed to compute the cohesive energy density (CED), solubility parameter (δ) and sorption of CO₂, H₂S, CH₄, O₂, and N₂ gases in polyamide membrane to corroborate theoretical study with experimentally determined gas transport properties.     

Gold nanorods with finely tunable longitudinal surface plasmon resonance as SERS substrates

Advances in nanophotonics have shown the potential of colloidal metal nanoparticles with sharp tips, such as rods, to focalize plasmonic electromagnetic fields. We report on the synthesis of Au nanorods via a seed mediated approach and the influence of silver ions on the aspect ratio of the Au nanorods. The longitudinal surface plasmon resonance (LSPR) of the Au nanorods was successfully tuned with the concentration of silver ions. The surface enhanced Raman scattering (SERS) effect of 2-aminothiophenol (2-ATP) as a probe molecule on Au nanorods was systematically studied by varying the longitudinal surface plasmon resonance of the nanorods. The highest electromagnetic enhancement was observed when the longitudinal surface plasmon resonance of the Au nanorods overlapped with the laser excitation wavelength. The variation of the SERS enhancement factor with the longitudinal surface plasmon resonance and laser excitation lines is also discussed in detail.     

Pervaporation of tertiary butanol/water mixtures through chitosan membranes cross‐linked with toluylene diisocyanate

Membranes made from 84% deacetylated chitosan biopolymer were cross‐linked by a novel method using 2,4‐toluylene diisocyanate (TDI) and tested for the separation of t‐butanol/water mixtures by pervaporation. The unmodified and cross‐linked membranes were characterized by Fourier transform infra red (FTIR) spectroscopy, X‐ray diffraction (XRD) studies and sorption studies in order to understand the polymer–liquid interactions and separation mechanisms. Thermal stability was analyzed by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) while tensile strength measurement was carried out to assess mechanical strength. The membrane appears to have good potential for breaking the aqueous azeotrope of 88.2 wt% t‐butanol by giving a high selectivity of 620 and substantial water flux (0.38 kg m^?2 hr^?1). The effects of operating parameters such as feed composition, membrane thickness and permeate pressure on membrane performance were evaluated. Copyright © 2005 Society of Chemical Industry     

mGDI based parallel adder for low power applications

Microsystem Technologies - The paper discusses a unique method to design low power circuits, which is called Gate Diffusion Input (GDI) method. Complex functions can be implemented using only two...     

Fracture Analysis of Concrete Structural Components Accounting for Tension Softening Effect

This paper presents methodologies for fracture analysis of concrete structural components with and without considering tension softening effect. Stress intensity factor (SIF) is computed by using analytical approach and finite element analysis. In the analytical approach, SIF accounting for tension softening effect has been obtained as the difference of SIF obtained using linear elastic fracture mechanics (LEFM) principles and SIF due to closing pressure. Superposition principle has been used by accounting for non-linearity in incremental form. SIF due to crack closing force applied on the effective crack face inside the process zone has been computed using Green's function approach. In finite element analysis, the domain integral method has been used for computation of SIF. The domain integral method is used to calculate the strain energy release rate and SIF when a crack grows. Numerical studies have been conducted on notched 3-point bending concrete specimen with and without considering the cohesive stresses. It is observed from the studies that SIF obtained from the finite element analysis with and without considering the cohesive stresses is in good agreement with the corresponding analytical value. The effect of cohesive stress on SIF decreases with increase of crack length. Further, studies have been conducted on geometrically similar structures and observed that (i) the effect of cohesive stress on SIF is significant with increase of load for a particular crack length and (iii) SIF values decreases with increase of tensile strength for a particular crack length and load.     

An Integrated Fracture Mechanics Based Approach for Non-Linear Analysis of Lightly Reinforced Concrete Beams

A non-linear fracture mechanics based approach is proposed to depict a typical fracture mechanism from initiation to growth, eventually leading to failure. This concept is developed for a lightly reinforced beam in flexure. The proposed model integrates the existing methodology of a Stress Intensity Factor equilibrium equation with the bridging forces developed in concrete cover and rebar. The model and solution algorithm outlined presents an elaborate understanding of the mechanism involved and is significant in predicting the behaviour of flexural members. The analysis is performed using MATLAB programming. The proposed approach ensures a maximum tolerable crack length and crack width for flexural members to prevent a catastrophic failure. Such an approach has the potential to serve as an analysis and design tool for reinforced concrete components subjected to normal conditions and towards deciding rehabilitation and strengthening measures.