Recovery of Ammonium Nitrate and Reusable Acetic Acid from Effluent Generated during HMX Production

Production of HMX on commercial scale is mainly carried out by modified Bachmann process, and acetic acid constitutes major portion of effluenttspent liquor produced during this process. The recovery of glacial acetic acid from this spent liquor is essential to make the process commercially viable besides making it eco-friendly by minimising the quantity of disposable effluent. The recovery of glacial acetic acid from spent liquor is not advisable by simple distillation since it contains, in addition to acetic acid, a small fraction of nitric acid, traces of RDX, HMX, and undesired nitro compounds. The process normally involves neutralising the spent mother liquor with liquor ammonia and then distillating the ueutralised mother liquor under vacuum to recover dilute acetic acid (strength approx. 30 %). The dilute acetic acid, in turn, is concentrated to glacial acetic acid by counter current solvent extraction, followed by distillation. The process is very lengthy and the energy requirement is also veryhigh, rendering the process economically unviable. Hence, a novel method has been developed on bench-scale to obtain glacial acetic acid directly from the mother liquor after the second ageing process

Mapping Divide-and-Conquer Algorithms to Parallel Architectures

24 pagesIn this paper, we identify the binomial tree as an ideal computation structure for parallel divide-and-conquer algorithms. We show its superiority to the classic full binary tree structure with respect to speedup and efficiency. We also present elegant and efficient algorithms for mapping the binomial tree to two interconnection networks commonly used in multicomputers, namely the hypercube and the two-dimensional mesh. Our mappings are optimal with respect to both average dilation and link contention. We discuss the practical implications of these results for message-passing architectures using store-and-forward routing vs. those using wormhole routing

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Parallel Divide and Conquer on Meshes

We address the problem of mapping divide-and-conquer programs to mesh connected multicomputers with wormhole or store-and-forward routing. We propose the binomial tree as an efficient model of parallel divide-and-conquer and present two mappings of the binomial tree to the 2D mesh. Our mappings exploit regularity in the communication structure of the divide-and-conquer computation and are also sensitive to the underlying flow control scheme of the target architecture. We evaluate these mappings using new metrics which are extensions of the classical notions of dilation and contention. We introduce the notion of communication slowdown as a measure of the total communication overhead incurred by a parallel computation. We conclude that significant performance gains can be realized when the mapping is sensitive to the flow control scheme of the target architecture

ompVerify: Polyhedral Analysis for the OpenMP Programmer

This chapter is the paper we presented at the 2011 international workshop on OpenMP. Many computational scientists choose to use their own programming skills to manage the distribution of work among computer processors, rather than trust this task to an automated system that is the typical and product of the mathematics and software (known as the polyhedral framework ) that has been produced by my research community. In this work, my co-authors and I show that this same mathematics and software can be used to help programmers catch mistakes in their hand-written software for work distribution. The article is available online at http://www.irisa.fr/prive/Antoine.Morvan/publis/iwomp.pdf. --author-supplied descriptio

Electron emissive properties of Pb and Bi containing glasses

Secondary electron emission (SEE) has been investigated for reduced Pb glass and bismuth containing V2O5-P2O5 and silicate glasses. The measurements of SEE coefficient, surface work function and ionization potential are reported. The systematic analysis of these results using Dionne's theory is given in view of their application in an electron multiplier. X-ray diffraction studies are also presented to confirm the metallic contents in these glasses