Life cycle assessment of ISPRA Mark 9 thermochemical cycle for nuclear hydrogen production

The nuclear energy driven thermochemical cycle is one of the potential water‐splitting processes for producing hydrogen, presumed to be the transportation fuel of the future. A life cycle assessment (LCA) of one such system, which utilizes nuclear energy to drive the ISPRA Mark 9 thermochemical cycle, is presented in this paper. The results of the LCA are presented in terms of the emissions of greenhouse gases (CO₂‐equivalent) and acid gases (SO₂‐equivalent). The contributions of the thermochemical plant to the emissions were determined through the estimation of material and energy requirements for chemical inventory, raw materials consumption and plant fabrication/installation. The greenhouse gas emissions from the system are 2515 g CO₂‐equivalent kg^?1 H₂ produced and acid gas emissions 11.252 g SO₂‐equivalent kg^?1 H₂ produced. A comparison of this hydrogen production route with other routes, including steam reforming of methane and high‐temperature electrolysis, is also presented in the paper. Copyright © 2006 Society of Chemical Industry     

Growth of a liquid film accompanied by a zero-order reaction

The growth of a thin liquid film surrounded by gas pocket(s), undergoing absorption with a zero-order chemical reaction, has been simulated by an apt mathematical model in order to study the influence of various parameters involved. The solution has been obtained semi analytically using Goodman's integral method and solving the resulting differential equation by a fourth-order Runge-Kutta numerical integration algorithm. The computations reveal the strong dependence of film growth on reaction rate, diffusivity, and molar volume whereas the effect of gas-pocket volume and initial film thickness are moderate.     

Architectural support for inter-stream communication in an MSIMD system

This paper considers hardware support for the exploitation of control parallelism on data parallel architectures. It is well known that data parallel algorithms may also possess control parallel structure. However, the splitting of control leads to data dependency and synchronization issues that were implicitly handled in conventional SIMD architectures. These include synchronization of access to scalar and parallel variables, and synchronization for parallel communication operations. We propose a sharing mechanism for scalar variables and identify a strategy which allows synchronization of scalar variables between multiple streams. The techniques considered are based on a bit-interleaved register file structure which allows fast copy between register sets. Hardware cost estimates and timing analyses are provided, and comparison with an alternate scheme is presented. The register file structure has been designed and simulated for the HP 0.8μm CMOS process, and circuit simulation indicates access times are less than six nanoseconds. In addition, the impact of this structure on system performance is also studied.     

Assessment of integrity of components in piping of 500 MWe PHWR: using R-6 method

The primary heat transport system of 500 MWe Indian PHWR comprises of straight pipes, elbows and headers. A study was conducted to qualify piping system for leak before break. R-6 method was used to assess integrity of system for leakage size crack (LSC), the margins on crack initiation load and unstable crack growth loads. Option 2 (material specific failure assessment diagram), Category 3 (ductile tearing) analysis was used for straight pipes, elbows and header. In order to enhance the confidence in the analytical results, detailed sensitivity analysis was also performed. For sensitivity analysis, variation in material properties, LSC was considered. The effect of variation in temperature on material properties was also considered. Tensile and fracture properties used for base and weld material data were generated from pipe material obtained from 220 MWe Nuclear Power Plant, under construction.     

Investigation of Gold Nanoparticle Inks for Low-Temperature Lead-Free Packaging Technology

Gold nanoparticle inks were investigated as a potential candidate for lead-free packaging applications. Inks consisted of surfactant-passivated nanoparticles dissolved in a solvent. Optimized gold inks are able to sinter at temperatures as low as 120°C and achieve conductivities of up to 70% of bulk. Once sintered, the metallic structure reverts to bulk-like properties and approaches bulk reliability and performance. Thus nanoparticle-based solders would operate at much lower homologous temperatures as compared with alloy-based solders. Nanoparticle inks under investigation were sintered at 180°C. The resulting material exhibited a resistivity of 5 μΩ cm, which is significantly lower than those of Pb-Sn and Sn-Ag-Cu. Electromigration studies were carried out and time to failure was investigated as a function of temperature. Electromigration activation energy was calculated through Black’s equation to be 0.52 eV, which is consistent with surface/grain boundary diffusion. These studies suggest that nanoparticle-ink-based films show excellent robustness, due to their irreversible conversion to bulk-like materials. Nanoparticle inks are thus promising candidates for next-generation lead-free solders.     

The fate of Listeria monocytogenes during the manufacture of Camembert-type cheese: A comparison between raw milk and milk treated with high hydrostatic pressure

Camembert-type cheese was produced from: raw bovine milk; raw milk inoculated with 2 or 4 log CFU/ml Listeria monocytogenes; raw milk inoculated with L. monocytogenes and subsequently pressure-treated at 500 MPa for 10 min at 20 °C; or uninoculated raw milk pressure-treated under these conditions. Cheeses produced from both pressure-treated milk and untreated milk had the typical composition, appearance and aroma of Camembert. Curd and cheese made from inoculated, untreated milk contained large numbers of L. monocytogenes throughout production. An initial inoculum of 1.95 log CFU/ml in milk increased to 4.52 log CFU/g in the curd and remained at a high level during ripening, with 3.85 log CFU/g in the final cheese. Pressure treatment inactivated L. monocytogenes in the raw milk at both inoculum levels and the pathogen was not detected in any of the final cheeses produced from pressure-treated milk. Therefore high pressure may be useful to inactivate L. monocytogenes in raw milk that is to be used for the production of soft, mould-ripened cheese.

Industrial relevance

This paper demonstrates the potential of high pressure (HP) for treatment of raw milk to be used in the manufacture of soft cheeses. HP treatment significantly reduced the level of Listeria monocytogenes in the raw milk and so allowed the production of safer non-thermally processed camembert-like soft cheese.     

A multiobjective thermodynamic optimization of a nanoscale Stirling engine operated with Maxwell‐Boltzmann gas

Recent developments in nanotechnology provided an opportunity to solve many complex problems in the field of energy. Performance investigation of the nanoscale thermal cycles can prove crucial in the development of efficient and less polluting energy system. Due to the influence of boundary phenomenon and quantum degeneracy effects, a nanoscale engine performs according to statistical quantum thermodynamics instead of classical thermodynamics. In this study, a nanoscale Stirling engine operating on an ideal Maxwell‐Boltzmann gas is investigated for multiobjective optimization. Optimization problem of Stirling cycle is formed considering the thermal efficiency, ecological coefficient of performance and entropy generation. An application example of a nanoscale Stirling engine is presented and solved using Heat Transfer Search algorithm. Maxwell‐Boltzmann gas restricted in a finite domain is studied and the effect of different parameters, such as surface area ratio, volume ratio, and temperature ratio of the domain, is investigated. Sensitivity analysis is carried out to identify the effect of design variables on the performance parameters. Further, influence of the source temperature and the number of particles of working fluid on the objective functions is studied and presented.     

Land surface deformation parameter estimation using persistent scatterer interferometry approach in an underground metal mining environment

Persistent scatterer interferometry (PSI) is a major advancement in radar interferometry for detecting and monitoring land deformation. PSI is the most advanced class of differential interferometric synthetic aperture radar (DInSAR) techniques. The technique conquers the main drawbacks of the conventional DInSAR technique by identifying radar targets having stable backscattering characteristics in time. These targets are termed as persistent scatterers (PSs). The higher the number of PSs for a study area the higher the accuracy of the results will be, which is most common for deformation analysis in urban areas. However, for non-urban or highly de-correlated areas, PSs density collapses significantly, which needs to increase for optimal results. For this purpose, partially coherent/distributed scatterers (DSs) are being exploited in addition to the PSs. The field surface of this study is one of the copper-rich mining belts in India, which consists of two major underground metal mines. Scatterer characterziation of the field surface under study suggests that most of the scatterers are DSs and very few scatterers under the influence of the mining zone are PSs. In addition to this, a preliminary investigation of deformation characteristics of the field surface under study reveals that the spatial extent of deformation is small/localized along with slow and non-linear deformation. Keeping in view scatterer and deformation characteristics of the field surface under study, in this research paper, a Quasi-Persistent Scatterer based PSI approach has been applied using high-resolution TerraSAR-X interferometric data stack (10 images) to generate deformation time series and deformation velocity. Furthermore, results obtained from the applied PSI approach and ground-based observations (using GNSS) have shown good agreement with each other, in the order of ?5.20?mm/year (LOS) and ?5.38?mm/year (subsiding), respectively.     

Natural disasters management using social internet of things

Multimedia Tools and Applications - Natural disasters are very unexpected in human life. The best prevention from such natural disasters is an early warning system which gives a good period to take...