Development of low-pH cements for immobilisation of intermediate level radioactive waste: Achievements and challenges

Although cementation is a widely recognized solidification/ stabilization process for immobilisation of Intermediate Level Radioactive Waste (ILRW), the low resistance to hyperalkaline pore waters compromises the effectiveness of the process when Portland Cement (PC) is employed. Moreover the manufacture of PC is responsible for significant CO2 emissions. In this context, low pH cements are environmentally more suitable and have emerged as a potential alternative for obtaining secure waste forms. This paper summarises the achievements on development of low-pH cements and the challenges of using these new materials for the ILRW immobilisation. The performance of waste forms is also discussed in terms of radionuclides release. Reactive magnesium oxide and magnesium phosphate cements are emphasised as they feature important advantages such as consumption of available constituents for controlling acid-base reactions, reduced permeability and higher density. Additionally, in order to identify new opportunities for study, the long-term modelling approach is also briefly discussed. Copyright © 2013 by ASME.

A review of TRIZ, and its benefits and challenges in practice

TRIZ (the theory of inventive problem solving) has been promoted by several enthusiasts as a systematic methodology or toolkit that provides a logical approach to developing creativity for innovation and inventive problem solving. The methodology, which emerged from Russia in the 1960s, has spread to over 35 countries across the world. It is now being taught in several universities and it has been applied by a number of global organisations who have found it particularly useful for spurring new product development. However, while its popularity and attractiveness appear to be on a steady increase, there are practical issues which make the use of TRIZ in practice particularly challenging. These practical difficulties have largely been neglected by TRIZ literature. This paper takes a step away from conventional TRIZ literature, by exploring not just the benefits associated with TRIZ knowledge, but the challenges associated with its acquisition and application based on practical experience. Through a survey, first-hand information is collected from people who have tried (successfully and unsuccessfully) to understand and apply the methodology. The challenges recorded cut across a number of issues, ranging from the complex nature of the methodology to underlying organisational and cultural issues which hinder its understanding and application. Another contribution of this paper, potentially useful for TRIZ beginners, is the indication of what tools among the several contained in the TRIZ toolkit would be most useful to learn first, based on their observed degree of usage by the survey respondents. © 2012 Elsevier Ltd. All rights reserved.

Future, opportunities and challenges of inkjet technologies

Inkjet printing relies on the formation of small liquid droplets to deliver precise amounts of material to a substrate under digital control. Inkjet technology is becoming relatively mature and is of great industrial interest thanks to its flexibility for graphical printing and its potential use in less conventional applications such as additive manufacturing and the production of printed electronics and other functional devices. Its advantages over traditional methods of printing include the following: it produces little or no waste, it is versatile because several different methods exist, it is noncontact, and it does not require a master template so that printed patterns can be readily modified on demand. However, the technology is in need of further development to become mainstream in emerging applications such as additive manufacturing (3D printing). This review contains a description of conventional and less common inkjet methods and surveys the current applications of inkjet in industry. This is followed by specific examples of the barriers, limitations, and challenges faced by inkjet technology in both graphical printing and manufacturing. © 2013 by Begell House, Inc.