An Evaluation of Primer Preseating in Small Caliber Cartridge Production

This work presents the findings of a study to quantify the relative effectiveness of the primer preseating operation in small caliber cartridge production. In theory, primer preseating would enable cartridge stamping tools to achieve deeper stamping penetration depths and subsequently, greater primer retention forces. This is because, with preseating incorporated in the existing small caliber cartridge production process, a cartridge stamping tool would be fully dedicated to performing the case stamping operation (rather than the simultaneous primer seating and case stamping operations it currently performs). The findings presented in this work include measured percentages of total stamping tool force dedicated to primer seating, stamping tool penetration depths with and without primer preseating and primer retention forces with and without primer preseating. These findings and their underlying principles were produced through a static force equilibrium analysis and finite element modeling and simulation studies.     

Cosmological Plebanski theory

We consider the cosmological symmetry reduction of the Plebanski action as a toy-model to explore, in this simple framework, some issues related to loop quantum gravity and spin-foam models. We make the classical analysis of the model and perform both path integral and canonical quantizations. As for the full theory, the reduced model admits two disjoint types of classical solutions: topological and gravitational ones. The quantization mixes these two solutions, which prevents the model from being equivalent to standard quantum cosmology. Furthermore, the topological solution dominates at the classical limit. We also study the effect of an Immirzi parameter in the model.     

Finite-Time Destruction of Entanglement and Non-Locality by Environmental Influences

Entanglement and non-locality are non-classical global characteristics of quantum states important to the foundations of quantum mechanics. Recent investigations have shown that environmental noise, even when it is entirely local in influence, can destroy both of these properties in finite time despite giving rise to full quantum state decoherence only in the infinite time limit. These investigations, which have been carried out in a range of theoretical and experimental situations, are reviewed here.     

Characterization of sealed radioactive sources: uncertainty analysis to improve detection methods

A radioactive ¹³⁷Cs source has been analyzed for the radioactive parent ¹³⁷Cs and stable decay daughter ¹³⁷Ba. The ratio of the daughter to parent atoms is used to estimate the date when Cs was purified prior to source encapsulation (an “age” since purification). The isotopes were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) after chemical separation. In addition, Ba was analyzed by isotope dilution ICP-MS (ID-ICP-MS). A detailed error analysis of the mass spectrometric work has been undertaken to identify areas of improvement, as well as quantifying the effect the errors have on the “age” determined. This paper reports an uncertainty analysis to identifying areas of improvement and alternative techniques that may reduce the uncertainties. In particular, work on isotope dilution using ICP-MS for the “age” determination of sealed sources is presented. The results will be compared to the original work done using external standards to calibrate the ICP-MS instrument.     

Microfluidic HPLC‐Chip devices with integral channels containing methylstyrenic‐based monolithic media

Polyimide HPLC‐Chip devices containing poly(methylstyrene‐bis‐p‐vinylphenyl)ethane (MS/BVPE) stationary phase within the device channels and with wall attachment were prepared by thermally initiated free radical polymerization. The microfluidic devices were coupled to both UV and MS detectors. The potential of the MS/BVPE monolith as an alternative separation media within chip devices was investigated by side‐by‐side comparisons to particulate media within commercial devices. The chromatographic behavior of this stationary phase was comparable to particulate media for separations of proteins as the average peak width at half‐height was equal (6.2 s) for a separation within 8 min under gradient elution conditions. The ability to control the porosity characteristics of the MS/BVPE monolith with changes in polymerization time also extended its utility into small analyte (< 500 Da) applications, although more optimization is needed to match conventional RP media for these applications. The good mechanical stability of the MS/BVPE monolith within the microdevices enabled excellent run‐to‐run repeatability (%RSD retention time (? 0.16) and chip‐to‐chip reproducibility (%RSD retention time (1.4). The use of this material within enrichment channels also shows its potential value in more complex work flows.     

X-ray Crystal Structures of Silver Based Molecules Containing 5,5′-Dimethyl-2,2′-bipyridine and 2,2′-bipyridine

Abstract  

The reaction of AgBF₄ with 5,5′-dimethy-2,2′-bipyridine and 2,2′-bipyridine yields three previously unreported compounds. The molecular structures of these compounds were obtained by single-crystal X-ray diffraction. Crystallization of 1 occurs in the centrosymmetric triclinic space group P-1 (No. 2) with a = 13.0069(6), b = 13.5903(6), c = 13.9489(6); and α = 95.677(2), β = 98.995(2), γ = 101.716(2) and Z = 6. Crystallization of 2 occurs in the centrosymmetric monoclinic space group C2/c (No. 15) with a = 23.413(3), b = 11.2116(13), c = 13.0653(13) and β = 123.074(3), and Z = 4. Crystallization of 3 occurs in the centrosymmetric triclinic space group P-1 (No. 2) with a = 12.6843(12), b = 12.8834(13), c = 12.9887(13), and α = 96.172(5), β = 95.149(5), γ = 98.051(6) and Z = 2. Details of the synthesis and the structural characterization of the title compounds are presented and discussed.     

Polychromatic Colorings of Plane Graphs

We show that the vertices of any plane graph in which every face is incident to at least g vertices can be colored by ⌊(3g−5)/4⌋ colors so that every color appears in every face. This is nearly tight, as there are plane graphs where all faces are incident to at least g vertices and that admit no vertex coloring of this type with more than ⌊(3g+1)/4⌋ colors. We further show that the problem of determining whether a plane graph admits a vertex coloring by k colors in which all colors appear in every face is in ℘ for k=2 and is -complete for k=3,4. We refine this result for polychromatic 3-colorings restricted to 2-connected graphs which have face sizes from a prescribed (possibly infinite) set of integers. Thereby we find an almost complete characterization of these sets of integers (face sizes) for which the corresponding decision problem is in ℘, and for the others it is -complete. Research of N. Alon was supported in part by the Israel Science Foundation, by a USA–Israeli BSF grant, and by the Hermann Minkowski Minerva Center for Geometry at Tel Aviv University. Research of R. Berke was supported in part by JSPS Global COE program “Computationism as a Foundation for the Sciences.” Research of K. Buchin and M. Buchin was supported by the Netherlands’ Organisation for Scientific Research (NWO) under BRICKS/FOCUS project no. 642.065.503. Research of P. Csorba was supported by DIAMANT, an NWO mathematics cluster. Research of B. Speckmann was supported by the Netherlands’ Organisation for Scientific Research (NWO) under project no. 639.022.707.     

Opportunistic timing and manipulation in Australian Federal Elections

In many parliamentary systems, election timing is an important decision made by governments in order to maximize their expected remaining life in power. Governments can also introduce policy or economic actions to enhance their popular standing and thus their chance of being re-elected. On the other hand, an oppositions’ natural objective is to gain power, and they will also apply controls through their own policies to reduce the governments’ chance of being re-elected. In this paper we employ a dynamic programming approach to determine the optimal timing for governments and oppositions to best utilize their limited resources. At each decision branch, the optimal control is interpreted as a Nash–Cournot equilibrium of a zero-sum political game which, in certain states, admits mixed strategy solutions. We perform a case study on the Australian Federal Election for House of Representatives.     

Mathematics and Science Integration: Models and Characterizations

The squeeze on instructional time and other factors increasingly leads educators to consider mathematics and science integration in an effort to be more efficient and effective. Unfortunately, the need for common understandings for what it means to integrate these disciplines, as well as the need for improving disciplinary knowledge, appears to continue to be significant obstacles to an integrated approach to instruction. In this study we report the results of a survey containing six instructional scenarios administered to thirty-three middle grades science and math teachers. Analysis of teacher responses revealed that while teachers applied similar criteria in their reasoning, they did not possess common characterizations for integration. Furthermore, analysis suggested that content knowledge serves as a barrier to recognizing integrated examples. Implications for professional development planners include the need to develop and provide teachers with constructs and parameters for what constitutes mathematics and science integration. Continued emphasis on improving teacher content knowledge in both mathematics and science is also a prerequisite to enabling teachers to integrate content.     

The third homology of the special linear group of a field

We prove that for any infinite field F, the map is an isomorphism for all n≥3. When n=2 the cokernel of this map is naturally isomorphic to , where is the nth Milnor K-group of F. We deduce that the natural homomorphism from to the indecomposable K₃ of F, , is surjective for any infinite field F.