Casimir forces for inhomogeneous planar media

Casimir forces arise from vacuum uctuations. They are fully understood only for simple models, and are important in nano- and microtechnologies. We report our experience of computer algebra calculations towards the Casimir force for models involving inhomogeneous dielectrics. We describe a methodology that greatly increases condence in any results obtained, and use this methodology to demonstrate that the analytic derivation of scalar Green's functions is at the boundary of current computer algebra technology. We further demonstrate that Lifshitz theory of electromagnetic vacuum energy can not be directly applied to calculate the Casimir stress for models of this type, and produce results that have led to alternative regularisations. Using a combination of our new computational framework and the new theory based on our results, we provide specic calculations of Casimir forces for planar dielectrics having permittivity that declines exponentially. We discuss the relative strengths and weaknesses of computer algebra systems when applied to this type of problem, and describe a combined numerical and symbolic computational framework for calculating Casimir forces for arbitrary planar models.Publisher PD

A Linear Programming Approach to Weak Reversibility and Linear Conjugacy of Chemical Reaction Networks

15 páginas, 2 figuras.-- The final publication is available at www.springerlink.comA numerically effective procedure for determining weakly reversible chemical reaction networks that are linearly conjugate to a known reaction network is proposed in this paper. The method is based on translating the structural and algebraic characteristics of weak reversibility to logical statements and solving the obtained set of linear (in)equalities in the framework of mixed integer linear programming. The unknowns in the problem are the reaction rate coefficients and the parameters of the linear conjugacy transformation. The efficacy of the approach is shown through numerical examples.Matthew D. Johnston and David Siegel acknowledge the support of D. Siegel’s Natural Sciences and Engineering Research Council of Canada Discovery Grant. Gàbor Szederkényi acknowledges the support of the Hungarian National Research Fund through grant no. OTKA K-83440 as well as the support of project CAFE (Computer Aided Process for Food Engineering) FP7-KBBE-2007-1 (Grant no: 212754).Peer reviewe

Prospectus, March 23, 1983

ADMISSION POLICIES CHIEF CAUSE OF RESIGNATION: PARKLAND WOMEN\u27S BASKETBALL COACH RESIGNS; News Digest; Monticello wins overall; Time out; C-U Happenings; MDA needs volunteer attendants; Lobby display appreciated; Club Notes; NJCAA coverage considered \u27poor\u27; Profile: DAP instructor Lake; Finances influence spring break decisions: Question: What are you going to be doing over spring break?; Failure to register for draft: Tangle of red tape threatens financial aid process; PC financial aid is business as usual; Urban League priority: find jobs; We Saw You On Campus; Central Illinois part of Tornado Alley; Believe it or not..; Eight-state area is the tornado capital of the world; Classified; Skylines; Trivia quiz; The Ramones are true \u27rock and roll\u27; Enter Oscars contest today; Trivia quiz dies; Sport shorts; Parkland College Softball Schedule; Parkland College Baseball Schedule; Parkland College Outdoor Track Schedule; 1983 Parkland College Indoor Track All-Americanshttps://spark.parkland.edu/prospectus_1983/1021/thumbnail.jp

HPC-GAP: engineering a 21st-century high-performance computer algebra system

Symbolic computation has underpinned a number of key advances in Mathematics and Computer Science. Applications are typically large and potentially highly parallel, making them good candidates for parallel execution at a variety of scales from multi-core to high-performance computing systems. However, much existing work on parallel computing is based around numeric rather than symbolic computations. In particular, symbolic computing presents particular problems in terms of varying granularity and irregular task sizes thatdo not match conventional approaches to parallelisation. It also presents problems in terms of the structure of the algorithms and data. This paper describes a new implementation of the free open-source GAP computational algebra system that places parallelism at the heart of the design, dealing with the key scalability and cross-platform portability problems. We provide three system layers that deal with the three most important classes of hardware: individual shared memory multi-core nodes, mid-scale distributed clusters of (multi-core) nodes, and full-blown HPC systems, comprising large-scale tightly-connected networks of multi-core nodes. This requires us to develop new cross-layer programming abstractions in the form of new domain-specific skeletons that allow us to seamlessly target different hardware levels. Our results show that, using our approach, we can achieve good scalability and speedups for two realistic exemplars, on high-performance systems comprising up to 32,000 cores, as well as on ubiquitous multi-core systems and distributed clusters. The work reported here paves the way towards full scale exploitation of symbolic computation by high-performance computing systems, and we demonstrate the potential with two major case studies

Hybrid Wing Body Multi-Bay Test Article Analysis and Assembly Final Report

This report summarizes work performed by The Boeing Company, through its Boeing Research & Technology organization located in Huntington Beach, California, under the Environmentally Responsible Aviation (ERA) project. The report documents work performed to structurally analyze and assemble a large-scale Multi-bay Box (MBB) Test Article capable of withstanding bending and internal pressure loadings representative of a Hybrid Wing Body (HWB) aircraft. The work included fabrication of tooling elements for use in the fabrication and assembly of the test article

Влияние супероксидного анион-радикала и глутатиона на липолиз в адипоцитах крыс при окислительном стрессе, индуцированном аллоксаном

Установлено, что в адипоцитах крыс при действии аллоксана развивается окислительный стресс, сопровождающийся увеличением спонтанного липолиза и ингибированием стимулированного агонистом beta2-адренорецепторов изопротеренолом липолиза. На основании полученных данных сделан вывод о влиянии активных форм кислорода, в частности супероксидного анион-радикала, и системы глутатиона на молекулярные механизмы изменения интенсивности липолиза в адипоцитах крыс в условиях окислительного стресса, индуцированного аллоксаном

Planning and Patching Proof

Polynomial interpretations are a useful technique for proving termination of term rewrite systems. We show how polynomial interpretations with negative coefficients, like x–1 for a unary function symbol or x–y for a binary function symbol, can be used to extend the class of rewrite systems that can be automatically proved terminating.Proceedings of the 7th International Conference, AISC 2004, Linz, Austria, September 22-24, 2004

Prospectus, December 16, 1982

CHRISTMAS GREETINGS; News Digest; Work, study can lead to burnout; Economy causes legendary benefactor to cut spending; Choral festival set; Season\u27s Greetings; Computer gift may affect family; Skylines; Christmas questions bring varied responses; Observance of Christmas has survived; Yule log symbol of holiday warmth; Will the real Kris Kringle please step forward; Victorian halls decked with garlands, mistletoe; Festive coffees lift spirits; Comic books aren\u27t just kid stuff anymore; Ryder rides into comeback trail; \u27Bah, humbug\u27 attitude can be changed; Buzz Galaxy saves Santa in the nick of time; \u27Rat\u27 release in time for holidays; Winter brings world-wide holiday celebrations; Begin looking for summer job now; Season for giving is also season for taking; Shoppers hunt for bargains; No matter how you say it, Happy Holidays; WILL planning holiday specials; Tree traditions of German origin; Create a tree of memories: Tradition is growing; Nativity source of art inspiration; Christmas Trees; Classified; Thanksgiving at Washington School; holiday season brings new movie blitz; It\u27s \u27Showtime!\u27; Holiday Trivia Quiz; Club Notes; Final Exam Schedule -- Fall \u2782; Christmas for the young at hearthttps://spark.parkland.edu/prospectus_1982/1000/thumbnail.jp

Prospectus, January 26, 1983

SPRING RECORD BROKEN; News Digest; Computer will provide basic data storage; Tea ceremony backed by 450 years of tradition; Student papers taken; Comedy auditions set; PMA wants members; Reality, not drama, taught; Play detective!; Parkland Invitational Tournament Jan. 14-15 1983; Classified; Apathy is disappointing; Skylines; Weapons training part of CJC plans; Spring brings another chance; Trivia quiz returns; Rundgren goes it alone; Nonsense makes sense; Benatar album is anti-bootleg effort; Championship, MVP award go to Cobras; Third ski trip next monthhttps://spark.parkland.edu/prospectus_1983/1026/thumbnail.jp

Superconductivity in a Mesoscopic Double Square Loop: Effect of Imperfections

We have generalized the network approach to include the effects of short-range imperfections in order to analyze recent experiments on mesoscopic superconducting double loops. The presence of weakly scattering imperfections causes gaps in the phase boundary $B(T)$ or $\Phi(T)$ for certain intervals of $T$, which depend on the magnetic flux penetrating each loop. This is accompanied by a critical temperature $T_c(\Phi)$, showing a smooth transition between symmetric and antisymmetric states. When the scattering strength of imperfections increases beyond a certain limit, gaps in the phase boundary $T_c(B)$ or $T_c(\Phi)$ appear for values of magnetic flux lying in intervals around half-integer $\Phi_0=hc/2e$. The critical temperature corresponding to these values of magnetic flux is determined mainly by imperfections in the central branch. The calculated phase boundary is in good agreement with experiment.Comment: 9 pages, 6 figure