OPTIMIZATION AND VALIDATION OF A CHEMICAL PROCESS FOR URANIUM, MERCURY AND CESIUM LEACHING FROM CEMENTED RADIOACTIVE WASTES

2015 ◽  
Vol 4 (2) ◽  
pp. 131-139
Author(s):  
Nicolas Reynier ◽  
Rolando Lastra ◽  
Cheryl Laviolette ◽  
Nabil Bouzoubaâ ◽  
Mark Chapman
Keyword(s):  
Sulfuric Acid ◽  
Chemical Process ◽  
Management Strategy ◽  
Fission Products ◽  
Concentrated Sulfuric Acid ◽  
Direct Leaching ◽  
The Cost ◽  
Optimized Conditions ◽  
Term Management

Canadian Nuclear Laboratories (CNL) is developing a treatment and long-term management strategy for a legacy cemented radioactive waste that contains uranium, mercury, and fission products. Extracting the uranium would be advantageous for decreasing the waste classification and reducing the cost of long-term management. The chemical leachability of 3 key elements (U, Hg, and Cs) from a surrogate cemented waste (SCW) was studied with several lixiviants. The results showed that the most promising approach to leach and recover U, Hg, and Cs is the direct leaching of the SCW with H2SO4 in strong saline media. Operating parameters such as particle size, temperature, pulp density, leaching time, acid and salt concentrations, number of leaching/washing steps, etc. were optimized to improve key elements solubilization. Sulfuric leaching in saline media of a SCW (U5) containing 1182 ppm of U, 1598 ppm of Hg, and 7.9 ppm of Cs in the optimized conditions allows key elements solubilisation of 98.5 ± 0.4%, 96.6 ± 0.1%, and 93.8 ± 1.1% of U, Hg, and Cs, respectively. This solubilization process was then applied in triplicate to 7 other SCWs prepared with different cements, liquid ratios, and at different aging times and temperatures. Concentrated sulfuric acid is added to the slurry until the pH is about 2, which causes the complete degradation of cement and the formation of CaSO4. Sulfuric acid is particularly useful because it produces a leachate that is amenable to conventional ion exchange technology for the separation and recovery of uranium.

scholarly journals Cost-effective Analysis of Proton Pump Inhibitors in Long-term Management of Gastroesophageal Reflux Disease: A Narrative Review

2019 ◽  
Vol 55 (5) ◽  
pp. 292-305
Author(s):  
Shazia Jamshed ◽  
Akshaya Srikanth Bhagavathula ◽  
Sheikh Muhammad Zeeshan Qadar ◽  
Umaira Alauddin ◽  
Sana Shamim ◽  
...  
Keyword(s):  
Cost Effectiveness ◽  
Gastroesophageal Reflux Disease ◽  
Cost Effective ◽  
The Other ◽  
Cost Effectiveness Ratio ◽  
On Demand ◽  
Step Down ◽  
The Cost ◽  
Term Management

Background: Gastroesophageal reflux disease (GERD) is a common gastrointestinal disorder that results from regurgitation of acid from the stomach into the esophagus. Treatment available for GERD includes lifestyle changes, antacids, histamine-2 receptor antagonists (H2RAs), proton pump inhibitors (PPIs), and anti-reflux surgery. Aim: The aim of this review is to assess the cost-effectiveness of the use of PPIs in the long-term management of patients with GERD. Method: We searched in PubMed to identify related original articles with close consideration based on inclusion and exclusion criteria to choose the best studies for this narrative review. The first section compares the cost-effectiveness of PPIs with H2RAs in long-term heartburn management. The other sections shall only discuss the cost-effectiveness of PPIs in 5 different strategies, namely, continuous (step-up, step-down, and maintenance), on-demand, and intermittent therapies. Results: Of 55 articles published, 10 studies published from 2000 to 2015 were included. Overall, PPIs are more effective in relieving heartburn in comparison with ranitidine. The use of PPIs in managing heartburn in long-term consumption of nonsteroidal anti-inflammatory drug (NSAID) has higher cost compared with H2RA. However, if the decision-maker is willing to pay more than US$174 788.60 per extra quality-adjusted life year (QALY), then the optimal strategy is traditional NSAID (tNSAID) and PPIs. The probability of being cost-effective was also highest for NSAID and PPI co-therapy users. On-demand PPI treatment strategy showed dominant with an incremental cost-effectiveness ratio of US$2197 per QALY gained and was most effective and cost saving compared with all the other treatments. The average cost-effectiveness ratio was lower for rabeprazole therapy than for ranitidine therapy. Conclusion: Our review revealed that long-term treatment with PPIs is effective but costly. To achieve long-term cost-effective approach, we recommend on-demand approach to treat heartburn symptoms, but if the symptoms persist, treatment with continuous step-down therapy should be applied.

The cost of omeprazole versus open anti-reflux surgery in the long-term management of reflux esophagitis

1998 ◽  
Vol 114 ◽  
pp. A238 ◽  
Author(s):  
HE Myrvold ◽  
L Lundell ◽  
B Liedman ◽  
J Hatlebakk ◽  
P Miettinen ◽  
...  
Keyword(s):  
Reflux Esophagitis ◽  
The Cost ◽  
Term Management

Population trend of feral camels in the Northern Territory, Australia

2004 ◽  
Vol 31 (5) ◽  
pp. 509 ◽  
Author(s):  
Glenn P. Edwards ◽  
Keith Saalfeld ◽  
Bretan Clifford
Keyword(s):  
Management Strategy ◽  
Management Practices ◽  
South Australia ◽  
Aerial Survey ◽  
Northern Territory ◽  
Foreseeable Future ◽  
Current Management ◽  
Perception Bias ◽  
Term Management

We conducted a broad-scale aerial survey between 20 August and 12 October 2001 to ascertain the distribution and abundance of feral camels in the southern part of the Northern Territory. There was a minimum of 80 533 feral camels in the Northern Territory at the time of the survey. This figure is corrected for perception bias (a result of observers missing animals that are potentially visible), but not for availability bias (a result of some animals being concealed from the observers). The population of feral camels in the Northern Territory increased at a mean annual exponential rate, r, of 0.093 between 1993 and 2001. This represents an increase of ~10% per year or an approximate doubling in population size every 8 years. This trend is likely to continue for the foreseeable future. We use the results of an earlier survey (which included the Northern Territory, South Australia and Western Australia) to give a minimum figure of 300 000 feral camels for Australia in 2001. We discuss what is known of the impacts of feral camels in Australia, the inadequacy of current management practices and issues to be considered in designing an effective long-term management strategy for the species.

The Price of Knowledge: Fisheries Management as a Research Tool

1978 ◽  
Vol 35 (2) ◽  
pp. 208-212 ◽  
Author(s):  
William Silvert
Keyword(s):  
Fisheries Management ◽  
Risk Taking ◽  
Management Strategy ◽  
Scientific Information ◽  
Economic Value ◽  
Short Term ◽  
Management Objectives ◽  
Term Management ◽  
Future Management

One of the side effects of fisheries management is the discovery of new scientific information. Since this information has economic value, in that it can be used to improve future management of the fishery, the information that can be gained through a particular management strategy should not be ignored in evaluating that strategy. This paper shows using a simple model, how the research component of fisheries management can be measured and used to plan an optimal strategy. The management objectives are taken to include avoidance of risk and maximization of yield. The results depend critically on the time horizon for management. Long-term management favors creative risk-taking and leads to optimal future exploitation, while management based on short-term considerations may freeze the fishery in a permanent pattern of suboptimal yields. Key words: fisheries management, optimal control

scholarly journals A New Equilibrium Strategy of Supply and Demand for the Supply Chain of Pig Cycle

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Changxiang Lu ◽  
Jiaqi Fang ◽  
Shaochuan Fu
Keyword(s):  
Supply Chain ◽  
Management Strategy ◽  
Market Research ◽  
Supply And Demand ◽  
Equilibrium Strategy ◽  
Price Rise ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
The Cost

The pig market had experienced a cycle of price rise and fall, also known as the “pig cycle.” This paper analyzes the fluctuation relationship between pig price, pig supply, and pork demand, constructs a system dynamics model of the pig industry by decomposing the structure of the pig supply chain, and then discusses the causes of “pig cycle,” as well as the supply chain management strategy and industrial policy, to stabilize the pig industry market. Research shows that reducing the cost of pig breeding, countercyclical adjustment, and government macrocontrol can effectively reduce the fluctuation of pig prices. Among them, reducing the pig breeding cost is the most effective long-term strategy to stabilize the pig price.

scholarly journals Long-Term Management After Variceal Bleed — The Current Role of Sclerotherapy

HPB Surgery ◽  
1991 ◽  
Vol 4 (1) ◽  
pp. 5-10
Author(s):  
P. C. Bornman ◽  
J. E. J. Krige ◽  
J. P. Dunn ◽  
J. Terblanche
Keyword(s):  
Management Strategy ◽  
Term Treatment ◽  
Current Status ◽  
Injection Sclerotherapy ◽  
Acute Variceal Bleeding ◽  
Variceal Bleed ◽  
Long Term Treatment ◽  
Term Management

While injection sclerotherapy has been accepted as the treatment of choice for acute variceal bleeding, its role as a definitive long-term treatment modality has not yet been clearly defined. This paper will critically analyse the current status of this technique, now widely used, and a comparison will be made with conventional medical management. The review will be based on the 10 years' Cape Town experience and the published series on this subject. A long-term management strategy will also be discussed.

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