Effects of hydrogen addition on structure and NO formation of highly CO-Rich syngas counterflow nonpremixed flames under MILD combustion regime

The present study has numerically investigated the Moderate or Intense Low oxygen Dilution (MILD) combustion regime, combustion processes and NO formation characteristics of the highly CO-rich syngas counterflow nonpremixed flames. To realistically predict the flame properties of the highly CO-rich syngas, the chemistry is represented by the modified GRI 3.0 mechanism. Computations are performed to precisely analyze the flame structure, NO formation rate, and EINO of each NO sub-mechanism. Numerical results reveal that the hydrogen enrichment and oxygen augmentation substantially influence the NO emission characteristics and the dominant NO production route in the CO-rich syngas nonpremixed flames under MILD and high temperature combustion regimes. It is found that the most dominant NO production routes are the NNH path for the lowest oxygen level (3%) and the thermal mechanism for the highest O₂ condition (21%). For the intermediate oxygen level (9%), the most dominant NO production routes are the NNH route for the hydrogen fraction up to 5%, the CO₂ path for the hydrogen fraction range from 5% to 10% and the thermal mechanism for the hydrogen fraction higher than 10%, respectively. To evaluate the contribution of the specific reaction on EINO the sensitivity coefficients are precisely analyzed for NO formation processes with the dominance of NNH/CO₂/Thermal mechanism under the highly CO-rich syngas flames.     

A review on global wind energy policy

With the increasing negative effects of fossil fuel combustion on the environment in addition to limited stock of fossil fuel have forced many countries to inquire into and change to environmentally friendly alternatives that are renewable to sustain the increasing energy demand. Energy policy plays a vital role to mitigate the impacts of global warming and crisis of energy availability. This paper explores the wind energy industry from the point of view of the wind energy policy. It is noticed that energy policy could help increasing wind power generation as well as stimulating the energy industry. It may be stated that without specific energy policy, a country would not be able to solve the acute problems like reducing greenhouse gases (GHGs) emission, scarcity of energy, etc. This paper discussed the existing successful energy policies for few selected countries. Based on literatures, it has been found that FIT, RPS, incentives, pricing law and Quota system are the most useful energy policies practiced by many countries around the world. Then, status of wind energy policy for Malaysia was investigated and compared with few selected countries around the world.     

The 5C model: A new approach to asset integrity management

As organizations grow more complex in operation and more global in scope, assets and technical integrity become key success factors. A company's asset integrity business process needs to be mapped in order to 1) provide a proper overview of operation and business processes, 2) identify all critical interfaces and 3) ensure that all gaps and overlaps in processes are eliminated.Achieving asset integrity requires companies to sustain their activities and identify the hazards, weaknesses and objectives of their strategic assets. Technical integrity emphasizes a complete overview of technical conditions and related information, and the ability of the companies to document the technical state of its assets. It is based on an integrated view of the current state of operations, and the identification of all critical interfaces, in order to ensure that all gaps and unnecessary overlaps in processes are eliminated.Companies look increasingly at their asset integrity management system as a means to extend the life of their assets, beyond the original design conditions and production capacity.Establishing an asset integrity management system requires the documentation of the company's technical integrity management, a strategy and the processes for carrying it out, identifying gaps; selecting corrective interventions and conducting follow up actions.The paper discusses various aspects of asset integrity management, including its planning and implementation. We begin with an introduction to asset technical integrity, provide some theoretical backgrounds, present a model we call 5C and conclude with a summary and discussion.     

Characterization of Al18B4O33 ceramic synthesized by the sol-gel,precipitation, and combustion methods

In this study, Al₁₈B₄O₃₃ aluminum borate is synthesized by the sol-gel, precipitation, and combustion methods, which use similar starting materials. Simultaneous thermal analyzer and Fourier transform infrared spectroscopy are employed to determine the thermal behavior and the chemical bonding structures. In addition, the crystal structure and microstructure are identified by X-ray diffraction and scanning electron microscope. The results reveal that Al₁₈B₄O₃₃ nanorods are produced by sol-gel method and citric acid controls the morphology of powders. Additionally, Al₁₈B₄O₃₃ phase is obtained by decomposing Al₄B₂O₉ unstable phase at 1000°C by sol-gel method. However, Al₁₈B₄O₃₃ phase is immediately obtained from calcination of an amorphous phase at 1000°C by precipitation and combustion methods.     

A study on inspection schemes in optimal design of control charts for deteriorating processes

The non-uniform inspection scheme obtained by the constant integrated hazard procedure overcomes the uniform scheme economically in optimal design of control charts. The comperative study is generalized in this paper to an optimization problem which looks for the optimal sampling points among all possible sampling schemes. The objective function is simplified here by modelling sequential time intervals as a family of functions of the first sampling interval, which also has been induced by the constant integrated hazard approach. The study demonstrates the model implementation through the economic design of $\overline{X}$ and T²-Hotelling control charts, both under the two widely used process failure mechanisms, that is, Weibull and Chen distributions. A comprehensive numerical investigation illustrates the possibility of existence of sampling schemes which outperform the constant integrated hazard approach and emphasizes the necessity of further investigation into the solution procedure.     

Elegance in the Age of Digital Technique

Ali Rahim and Hina Jamelle of Contemporary Architecture Practice introduce this issue of AD by exploring how elegance represents a maturity in digital design practice. In order to undertake this new level of formal sophistication, mastery of technique and innate creative ability have to be combined with a multilayered design complexity. It is only then that the architect is able to fully tackle the multiple constraints and external demands of a project in gestation. Copyright © 2007 John Wiley & Sons, Ltd.