Reducing nuclear danger through intergovernmental technical exchanges on nuclear materials safety management

The United States (U.S.) and Russia are dismantling nuclear weapons and generating hundreds of tons of excess plutonium and high-enriched uranium fissile nuclear materials that require disposition. The U.S. Department of Energy and the Ministry of the Russian Federation for Atomic Energy (Minatom) organizations are planning and implementing safe, secure storage and disposition operations for these materials in numerous facilities. This provides a new opportunity for technical exchanges between Russian and U.S. scientists that can establish an improved and sustained common safety culture for handling these materials. An initiative that develops and uses personal relationships and joint projects among Russian and U.S. participants involved in nuclear materials safety management contributes to improving nuclear materials nonproliferation and to making a safer world. Technical exchanges and workshops are being used to systematically identify opportunities in the nuclear materials facilities to improve and ensure the safety of workers, the public, and the environment.     

Challenges in the valorisation of chitinous biomass within the biorefinery concept

The sustainable production and use of biomass for food, structural material and packaging has become part of global development strategies. Efforts have increased in research and development (R&D) of greener energy, agriculture and manufacturing, aiming toward zero waste. However, waste is often unavoidable and needs to be considered as a new opportunity within the context of a biorefinery. Our focus is on the valorisation of chitinous biomass, in particular chitin and chitosan which is considered as the second most abundant biopolymer on earth after cellulose. Biomass and food waste that can serve as a rich source of chitin comes from diverse origins. Chitin can also be considered as a source of platform chemicals enabled by novel green catalysts. In our opinion, a more holistic evaluation of the chitinous biomass waste supply chains are required. The economics of scale will determine the future trends in R&D of chitin derived products.     

Achieving maximum ROI from corporate databases: exploiting your databases with integrated querying for better decision-making

In order to increase the rate of drug discovery, pharmaceutical and biotechnology companies spend billions of dollars a year assembling research databases. Current trends still indicate a falling rate in the discovery of New Molecular Entities (NMEs). It is widely accepted that the data need to be integrated in order for it to add value. The degree to which this must be achieved is often misunderstood. The true goal of data integration must be to provide accessible knowledge. If knowledge cannot be gained from these data, then it will invalidate the business case for gathering it. Current data integration solutions focus on the initial task of integrating the actual data and to some extent, also address the need to allow users to access integrated information. Typically the search tools that are provided are either restrictive forms or free text based. While useful, neither of these solutions is suitable for providing full coverage of large numbers of integrated structured data sources. One solution to this accessibility problem is to present the integrated data in a collated manner that allows users to browse and explore it and also perform complex ad-hoc searches on it within a scientific context and without the need for advanced Information Technology (IT) skills. Additionally, the solution should be maintainable by 'in-house' administrators rather than requiring expensive consultancy. This paper examines the background to this problem, investigates the requirements for effective exploitation of corporate data and presents a novel effective solution.     

On a conjecture of optimal repair-replacement strategies for warranted products

Under a free replacement warranty policy, the manufacturer has the option of rectifying a failure by either repairing the failed item or replacing it with a new one. In [N. Jack, F. Van der Duyn Schouten, Optimal repair-replacement strategies for a warranted product, Int. J. Prod. Econ. 67 (2000) 95–100] a conjecture is made on the optimality of an age-limit policy: there exists a control limit , such that a minimal repair is performed on failure with t time units remaining in the warranty period if the age of the failing unit is less than or equal to . In this paper, we prove that this conjecture is indeed correct. Moreover, we show that for a more general model where the repair cost is random, a generalized repair-cost-limit policy is optimal, and the age-limit policy becomes its degenerated form. Numerical examples are provided to illustrate the computational algorithm and to compare the performance of these policies.     

Using principal components in a proportional hazards model with applications in condition-based maintenance

This paper proposes the application of a principal components proportional hazards regression model in condition-based maintenance (CBM) optimization. The Cox proportional hazards model with time-dependent covariates is considered. Principal component analysis (PCA) can be applied to covariates (measurements) to reduce the number of variables included in the model, as well as to eliminate possible collinearity between the covariates. The main issues and problems in using the proposed methodology are discussed. PCA is applied to a simulated CBM data set and two real data sets obtained from industry: oil analysis data and vibration data. Reasonable results are obtained.     

Two optimization models of the optimum inspection problem

This paper deals with establishing an optimum inspection schedule for systems that are subject to random failure and where the failure can be detected only through an inspection. The paper reviews ‘classical’ optimum checking policies. Two new optimization models are proposed to find the optimum sequence of inspection times. Theoretical analysis and numerical examples show that the optimum inspection time sequence derived from the proposed models is relatively accurate, robust, and computationally simple.