Redox Kinetics Study of Fuel Reduced Ceria for Chemical-Looping Water Splitting

Chemical-looping water splitting is a novel and promising technology for hydrogen production with CO₂ separation. Its efficiency and performance depend critically on the reduction and oxidation (redox) properties of the oxygen carriers (OC). Ceria is recognized as one of the most promising OC candidates, because of its fast chemistry, high ionic diffusivity, and large oxygen storage capacity. The fundamental surface redox pathways, including the complex interactions of mobile ions and electrons between the bulk and the surface, along with the adsorbates and electrostatic fields, remain yet unresolved. This work presents a detailed redox kinetics study with emphasis on the surface ion-incorporation kinetics pathway, using time-resolved and systematic measurements in the temperature range 600–1000 °C. By using fine ceria nanopowder, we observe an order-of-magnitude higher hydrogen production rate compared to the state-of-the-art thermochemical or reactive chemical-looping water splitting studies. We show that the reduction is the rate-limiting step, and it determines the total amount of hydrogen produced in the following oxidation step. The redox kinetics is modeled using a two-step surface chemistry (an H2O adsorption/dissociation step and a charge-transfer step), coupled with the bulk-to-surface transport equilibrium. Kinetics and equilibrium parameters are extracted with excellent agreement with measurements. The model reveals that the surface defects are abundant during redox conditions, and charge transfer is the rate-determining step for H₂ production. The results establish a baseline for developing new materials and provide guidance for the design and the practical application of water splitting technology (e.g., the design of OC characteristics, the choice of the operating temperatures, and periods for redox steps, etc.). The method, combining well-controlled experiment and detailed kinetics modeling, enables a new and thorough approach for examining the defect thermodynamics in the bulk and at the surface, as well as redox reaction kinetics for alternative materials for water splitting

Web Service Discovery in a Semantically Extended UDDI Registry: the Case of FUSION

Service-oriented computing is being adopted at an unprecedented rate, making the effectiveness of automated service discovery an increasingly important challenge. UDDI has emerged as a de facto industry standard and fundamental building block within SOA infrastructures. Nevertheless, conventional UDDI registries lack means to provide unambiguous, semantically rich representations of Web service capabilities, and the logic inference power required for facilitating automated service discovery. To overcome this important limitation, a number of approaches have been proposed towards augmenting Web service discovery with semantics. This paper discusses the benefits of semantically extending Web service descriptions and UDDI registries, and presents an overview of the approach put forward in project FUSION, towards semantically-enhanced publication and discovery of services based on SAWSDL

Growth performance of Catenella nipae on bamboo poles in the inter-tidal mangrove swamps of Chittagong coast

Macro-benthic algae Catenella nipae was cultured from November '06 to August '07 at the Salimpur planted mangrove area of Chittagong Coast. Growth of the cultured C. nipae on bamboo poles was measured during the investigation period. Average growth of C. nipae on bamboo poles was recorded 0.19cm/day. Physico-chemical parameters of water and soil were recorded during culture period in the tidal swamp of Salimpur mangrove area. Water temperature ranges from 24.0 to 31.5˚C, salinity from 6.0 to 21.0‰, dissolved oxygen (DO) from 3.8 to 5.8ml/l, water pH from 7.2 to 8.4, total dissolved solids (TDS) from 410 to 598mg/l, , total suspended solids (TSS) from 50 to 118mg/l, Total alkalinity from 95 to118 ppm, NO2-N from 0.18 to 0.47mg/l, NO3-N from 0.56 to 0.69mg/l, PO4-P from 0.90 to1.10 mg/l, HCO3 from 69.88 to 93.80mg/l, were recorded during culture period. Soil organic carbon, organic matter, soil PO4-P, soil pH were ranges from 2.22-2.37%, 4.22-4.51%, 1.10-1.39mg/100g and 5.9-6.7, respectively in the culture area. Growth of C. nipae showed a significant positive relation with water and soil parameters such as dissolved oxygen (DF=17, P=0.006, t=3), NO3-N concentration (DF=17, P=0.055, t=2) and a negative correlation with HCO3 concentration (DF=17, P=0.004, t=3). Physico-chemical parameters of both water and soil revealed that the coastal area of Salimpur could be a significant place for commercial culture of seaweeds C. nipae in Bangladesh.</jats:p

Design and Development of Superconducting Parallel-Bar Deflecting/Crabbing Cavities

The superconducting parallel-bar cavity is a deflecting/crabbing cavity with attractive properties that is being considered for a number of applications. We present the designs of a 499 MHz deflecting cavity developed for the Jefferson Lab 12 GeV Upgrade and a 400 MHz crabbing cavity for the LHC High Luminosity Upgrade. Prototypes of these two cavities are now under development and fabrication

Relationship between Interest Rate and Stock Price: Empirical Evidence from Developed and Developing Countries

Stock exchange and interest rate are two crucial factors of economic growth of a country. The impacts of interest rate on stock exchange provide important implications for monitory policy, risk management practices, financial securities valuation and government policy towards financial markets. This study seeks evidence supporting the existence of share market efficiency based on the monthly data from January 1988 to March 2003 and also shows empirical relationship between stock index and interest rate for fifteen developed and developing countries- Australia, Bangladesh, Canada, Chile, Colombia, Germany, Italy, Jamaica, Japan, Malaysia, Mexico, Philippine, S. Africa, Spain, and Venezuela. Stationarity of market return is tested and found none of this stock market follows random walk model, means not efficient in weak form. To investigate the reasons of market inefficiency, relationship between share price and interest rate, and changes of share price and changes of interest rate were determined through both time series and panel regressions. For all of the countries it is found that interest rate has significant negative relationship with share price and for six countries it is found that changes of interest rate has significant negative relationship with changes of share price. So, if the interest rate is considerably controlled for these countries, it will be the great benefit of these countries’ stock exchange through demand pull way of more investors in share market, and supply push way of more extensional investment of companies