Multi-level simulation of metal-forming processes

The IBF has for some years made use of finite element programmes to solve metal-forming problems. In the course of this investigation, it has become evident that a problem-oriented adaptation of FEM simulation to the problem in hand is beneficial in terms of computation effort. The computation time for the process parameters is optimised in a multi-level simulation. At level 1 (global analysis) integral parameters such as the required force and required work are computed using a coarse FEM mesh. At level 2 (local analysis) an optimised number of elements is used to determine continuum mechanics parameters like stress, strain and temperature. Microscopic phenomena are simulated at level 3 (microscopic analysis), using special micro-material elements and thermodynamic models.     

Alternating,all-trans polyenynes: Model compounds for poly(diacetylene)s with defined conjugation length

The syntheses of polyenynes as model compounds for poly(diacetylene)s (PDAs) are described. Variation of properties (UV–VIS, Raman, NMR and bond geometries) as a function of the chain length was investigated. After extrapolation to infinite chain length these data were compared to those for PDAs. From UV–VIS spectra a value of λ = 551 nm (2.25 eV) was calculated corresponding to the electronic transition of a single polyenyne chain. This energy is located at the low energy end of a yellow PDA solution spectrum. From Raman scattering v_(C?C) = 2108–2128 cm^?1 and v_(C?C) = 1505–1532 cm^?1 were calculated after extrapolation. Similarly sp-C¹³C NMR data yielded a shift of δ = 100 ppm. These data are almost identical to data known for yellow PDA solutions. Bond geometries are almost identical to those of poly(diacetylene)s and theoretical data.     

Myelination of the brain in MRI: a staging system

CORT has been developed to treat recurrent gynaecological malignancies infiltrating the pelvic wall unilaterally. The surgical part consists of: (i) staging laparotomy/lymphadenectomy, (ii) maximum tumour resection at the pelvic wall and exenteration of infiltrated central pelvic organs, (iii) implantation of guiding tubes on the residual tumour/tumour bed on the pelvic wall, (iv) pelvic wall plasty with muscle, musculocutaneous and omentum flaps, (v) operative reconstruction of bowel, bladder and perineo-vulvo-vaginal functions. Radiation is performed as interstitial high dose rate brachytherapy through the implanted tubes. Patients without prior pelvic irradiation receive in addition, whole pelvis teletherapy. CORT has been evaluated in a prospective phase I and II trial at the University of Mainz. Within a 3-year period, 21 patients with pelvic wall recurrences from various gynaecological primary tumours were treated. Seventeen patients had been irradiated as (part of) the previous therapy with a median total mid-pelvic dose of 65 Gy (range 40-100 Gy). There was no operative mortality. Five patients developed complications necessitating surgical intervention. One patient died from fatal thromboembolism 6 months after CORT without evidence of tumour progression. In 14 patients, local tumour control has been achieved. After a median follow-up period of 27 months (range 6-38 months) Kaplan-Meier life table analysis revealed an actuarial survival probability of 55% (recurrence-free 49%). We conclude from these preliminary results, that the CORT procedure for the treatment of pelvic wall recurrences is feasible and may lead to encouraging therapeutic success in selected patients, whose situation had been hopeless so far.     

More applicable environmental scanning systems leveraging “modern” information systems

With Ansoff’s article about weak signals as a flagship example, a substantial body of knowledge about environmental scanning systems exists. However, these concepts often go unused in practice. The 2008/2009 economic crisis provided a strong, ongoing impulse for redesigning such information systems (IS). This article develops six guidelines for the conceptual design of environmental scanning systems that are more applicable than those specified by previous research. We start with literature research, which reveals three gaps in existing approaches. Then we develop design guidelines to fill these gaps with the help of “modern” IS. To address the lack of sound requirements analysis, our first design principle proposes 360-degree environmental scanning systems for executives and suggests how to select the most important scanning areas. Three further findings cover weaknesses in the IS model perspective, focusing on more effective implications of weak signals. In terms of method, we propose incorporating scanning results more closely into executives’ decision-making processes. Applying the design guidelines at a raw materials and engineering company, we arrive at a prototype we call the “corporate radar.” It includes an IS-based tree with economic value added at risk on top. The resulting lessons learned help to evaluate our findings and the research method presented here, as well provide concrete starting points for future research.     

The liberalized δ-rule in free variable semantic tableaux

In this paper we have a closer look at one of the rules of the tableau calculus presented by Fitting [4], called the -rule. We prove that a modification of this rule, called the ⁺-rule, which uses fewer free variables, is also sound and complete. We examine the relationship between the ⁺-rule and variations of the -rule presented by Smullyan [9]. This leads to a second proof of the soundness of the ⁺-rule. An example shows the relevance of this modification for building tableau-based theorem provers.     

Tests and Proofs

This special issue collects current advances in the ongoing attempt to obtain synergies from the combination of Tests and Proofs.     

Mass-controlled capillary viscometer for a Newtonian liquid: viscosity of water at different temperatures

The operation principle of the mass-controlled capillary viscometer is presented for a Newtonian liquid. The derived equation for the temporal changes of the mass in a liquid column draining under gravity through a discharge capillary tube accounts self-consistently for the inertial convective term associated with the acceleration effect. The viscosity of water measured at different temperatures using the new approach is in good agreement with literature data.     

Solid state reaction in sandwich-type Al/Cu thin films

Al/Cu/Al and Cu/Al/Cu triple layers with approximately 10 nm single layer thickness deposited on tungsten substrates were analyzed in the early stages of reactive interdiffusion by means of atom probe tomography. The first reaction product is found after 5 min thermal treatment at 110 degrees C and identified by direct chemical analysis to be Al2Cu. Surprisingly, we found a significant asymmetry in the reaction rate of the new phase with the stacking sequence: the thickness of the product grown at the interfaces, at which Cu is deposited on top of the Al layer, is approximately 1.5-2 times thicker than the other one at the interfaces at which Al is deposited onto a Cu layer. On the other hand, at both interfaces the thickness of the product layer depends parabolically on time. No precursory interdiffusion and no distinct nucleation process of the product are observed.