Calculation of strain from an object grating on a reseau film

A correlation technique for the automatic calculation of grating coordinates in digital images is presented yielding displacements and strain on plane surfaces with an accuracy of 100 to 300 microstrain. It is shown that a large grating area can be investigated when the object grating is filmed by a reseau camera. Each segment of the negative can be digitized with a high-resolution CCD-camera resulting in a global resolution of about 6000^*6000 pixels in the whole image. To improve the accuracy of the grating coordinates and to avoid segmentation errors at the overlapping edges, the distortion of the CCD-camera and of the digitizing setup is corrected by a two-dimensional polynomial function. This is derived from the distortion of a digitized image of a high-precision reference grating. The strain calculation considers large deformations as well as rigid-body rotation.     

Spatially resolved Raman scattering for multi-species and temperature analysis in technically applied combustion systems: Spray flame and four-cylinder in-line engine

Spatially resolved Raman scattering is used to measure the single shot stoichiometry before ignition inside a realistic internal combustion engine with high single shot precision of l%–4% (depending on the extent of spatial averaging). The high precision results from the simultaneous detection of fuel and N₂ (O₂), which yields stoichiometry via a relative measurement. The cycle-to-cycle fluctuations of stoichiometry are clearly resolved. The feasibility of averaged spatially resolved simultaneous multi-species detection is demonstrated in a commercial oil-burning furnace as well. The limited precision that is usually obtained in Raman scattering by interfering emissions is highly improved using the fact that the interfering emission is unpolarized whereas Raman scattering is highly polarized. Therefore, Raman measurements provided good signal-to-noise ratios in the spray flame even in the area where fuel droplets occur and during combustion in the engine. The optical multichannel analyzer yields one-dimensional spatial resolution, and offers the capability to easily combine Raman scattering with Rayleigh scattering and laser-induced fluorescence detection of minority species.     

Calcium hydride and deuteride studied by neutron diffraction and NMR

The structure of CaD₂ has been redetermined by neutron diffraction and the structure has been confirmed by NMR measurements. However, the interpretation of the NMR measurements is not easy. The unsymmetrical position of the hydrogen (deuterium) atoms and the large range of interatomic distances lead to complicated spectra. Since the spectra for both the hydride and the deuteride seem to be determined mainly by dipolar interactions, one can conclude that the electric field gradient at the D sites must be very small. Line narrowing above 440°K is ascribed to proton diffusion with an activation enthalpy of 17.4 kcal/mol.     

A fast numerical method to solve radial coupled equations for electronic excitation in heavy particle collisions

In calculations of the electronic excitation for heavy particle collisions one has to deal with coupled equations, for which the numerical treatment requires very large computer times. A method is presented that allows to reduce the computer time drastically, so that it is possible to calculate electronic excitation problems with reasonable effort.     

Hammet correlations for the solvolysis of silylpyrroles

The siliconnitrogen bond in (XC₆H₄)Me₂SiNC₄H₄ (X = p-MeO, p-Me, m-Me, H, p-Cl) is cleaved in absolute ethanol containing sulphuric acid or amine buffers. The logarithms of the rate constants correlate with σ^o-constants, the p-values being -0.97 for the acid-catalysed reaction, and +1.8 and +2.6 for the reactions catalysed by amine and ethoxide anion, respectively. Mechanisms involving pentacoordinate silicon are suggested.     

Any 7-Chromatic Graphs Has K 7 Or K 4,4 As A Minor

In 1943, Hadwiger made the conjecture that every k-chromatic graph has a K _k -minor. This conjecture is, perhaps, the most interesting conjecture of all graph theory. It is well known that the case k=5 is equivalent to the Four Colour Theorem, as proved by Wagner [39] in 1937. About 60 years later, Robertson, Seymour and Thomas [29] proved that the case k=6 is also equivalent to the Four Colour Theorem. So far, the cases k7 are still open and we have little hope to verify even the case k=7 up to now. In fact, there are only a few theorems concerning 7-chromatic graphs, e. g. [17].In this paper, we prove the deep result stated in the title, without using the Four Colour Theorem [1,2,28]. This result verifies the first unsettled case m=6 of the (m,1)-Minor Conjecture which is a weaker form of Hadwigers Conjecture and a special case of a more general conjecture of Chartrand et al. [8] in 1971 and Woodall [42] in 1990.The proof is somewhat long and uses earlier deep results and methods of Jørgensen [20], Mader [23], and Robertson, Seymour and Thomas [29].* Research partly supported by the Japan Society for the Promotion of Science for Young Scientists. Research partly supported by the Danish Natural Science Research Council.Dedicated to Professor Mike Plummer on the occasion of his sixty-fifth birthday.     

Search for evidence of nuclear involvement in the fatal explosion of a “cold fusion” experiment

Forensic analyses of debris from the fatal explosion of an electrochemical cold fusion cell at SRI International were conducted at LLNL at the request of Cal-OSHA. One investigation focused on the possibility of conventional nuclear reaction mechanisms contributing to the total energy inventory of the incident. Selected metal components of the electrolysis apparatus were subjected to nondestructive -ray spectrometry with high-sensitivity, low-background Ge detector systems. The anticipated analytes in these studies were radioactivation products potentially induced in the explosion residue by either fast or thermal neutrons. The results of this investigation were negative within the temporal constraints of the incident and the analytical sensitivities of the instrumentation.     

Sorption of dissolved galactoglucomannans and galactomannans to bleached kraft pulp

Sorption of mannans onto bleached kraft pulp (BKP) was investigated withreference to other interactions of mannans in mechanical pulping andpapermaking. O-Acetyl galactoglucomannans (GGM) isolated from thermomechanicalpulp (TMP), as well as enzymatically modified guar gum galactomannans (GM) wereused in the study. The results showed that deacetylation of TMP GGMs, alsooccurring during peroxide bleaching of TMP, dramatically increased thesorption.A higher sorption was also achieved after salt addition, while temperature hadno effect. Sorption of guar gum GMs onto BKP fibres was, on the other hand,quite unaffected by external conditions such as temperature, pH and saltaddition. The degree to which the pulp was beaten did not notablyinfluence the sorption either – only unbeaten pulp gave a clearly lower mannansorption. A lower number of galactose side groups, however, strongly affectedsorption – the lower the number of side groups, the higher the sorption.The molar mass did not seem to affect the rate of sorption to any higher extentat ambient temperature. At higher temperatures the rate of sorption of smallerGM polymers was, nevertheless, slightly increased. Low-molar-mass GMs alsosorbed at a higher rate onto unbeaten pulp compared to high-molar-mass mannans.GM sorption appeared to be virtually irreversible.     

2-Alkynylcyclopent-2-enols from 2-Alkynylcyclohex-2-enones via 1-Alkynyl-7-oxabicyclo[4.1.0]heptan-2-ones

2-Alkynylcyclohex-2-enones 1a–c and 2a–c react with H₂O₂/NaOH in MeOH to afford 1-alkynyl-7-oxabicyclo[4.1.0]heptan-2-ones 3a–c and 4a–c , respectively. The 3-unsubstituted bicyclic epoxy ketones 3a, 3b , and 4a, 4b react further with H₂O₂/NaOH, undergoing ring contraction and (formal) decarbonylation to give 2-alkynylcy-clopent-2-enols 5a, 5b , and 6a, 6b , respectively. Epoxy ketones 3 are also obtained under neutral conditions on irradiation (λ = 350 nm) of cyclohexenones 1 in air-saturated benzene solution. Similarly, under neutral conditions oxo-cycloalkenecarbonitriles 8 react (thermally) with H₂O₂ in MeCN to give the oxabicyclic carbonitriles 9 .     

5,5-Dimethyl-1,4,2-dioxazoles as versatile aprotic hydroxamic acid protecting groups

5,5-Dimethyl-1,4,2-dioxazoles are readily installed by transketalization of 2,2-diethoxypropane, where both the NH and OH moieties are protected in a nonprotic form. The dioxazoles are stable to a wide variety of reaction conditions and readily revert back to the hydroxamic acid by treatment with Nafion-H in 2-propanol. The method is applicable to primary, secondary, tertiary, and aromatic hydroxamic acids, and the acidity of the protons adjacent to the dioxazole allows alpha-functionalization.