Structural Characterization of Aluminum Phosphate Binder

The chemical structure of aluminum phosphate binder, which is used as a sealant for thermally sprayed coatings, was studied. Powder X-ray diffraction (XRD) analysis showed that the binder was a mixture of several phases. None of these phases could be identified from the powder XRD data only. Electron diffraction revealed several distinct microcrystalline phases. The predominated phase was analyzed in more detail. The three-dimensional reciprocal lattice was reconstructed from a tilt series of electron-diffraction patterns that indicated that the main phase was the cyclohexaphosphate Al₂P₆O₁₈. The similarity of the intensity distribution in the observed and simulated electron-diffraction patterns of Al₂P₆O₁₈ confirmed this observation. The following unit-cell parameters were determined from the reconstructed reciprocal lattice: a = 8.8(7) Å, b = 15.5(6) Å, and c = 6.3(9) Å, β= 108°, and Z = 2. The reflection conditions indicated that the space group was P 2₁/ a .     

Applications of UV-nanoimprint soft stamps in fabrication of single-frequency diode lasers

We show how to use a modified poly-dimethyl-siloxane (PDMS) soft stamp to reduce pattern deformation and residual layer thickness in soft UV-nanoimprint lithography. A soft stamp thinned with toluene reduces the residual layer of a resist by as much as 50% compared to an unthinned stamp. We apply the soft UV-nanoimprint to prepare nanopatterned waveguides for a single-frequency diode laser. This laser operates with a side-mode suppression ratio of 50 dB, which indicates that the patterns are precise and uniform over the whole imprint field. To the best of our knowledge, this is the first single-frequency laser fabricated by soft UV-nanoimprint technology.     

Revisiting Private Water Proposals and Concessions of the 1870 and 1880s in Finland

Abstract

The paper questions the ethics of buying and reselling the concessions of water undertakings at the expense of consumer-owners. In Tampere, in 1866, an industrialist proposed a concession which would have provided him a good guaranteed return with the town assuming all risks. In Helsinki, in 1871, a concession of 75 years was signed with a private businessman. He did not even try to start operations but sold the concession further to a German company making a fortune. Due to the European-wide recession, the city bought back the concession. In 1885, the same entrepreneur got the horse-driven tram concession—tried this time to operate it but was unsuccessful. Some 110 years later several donors started to promote the idea of water concessions and other private operating contracts as a “new innovation.” By the early 21^st century, it became clear that private water multinationals are not willing to take the risk of making such investments in developing and transition economies. Before making such strategic decisions cities should make proper feasibility studies and compare the pros and cons of various options.     

Multitubular reactor design as an advanced screening tool for three-phase catalytic reactions

A parallel throughput screening system coupled with GC/MS analysis system was constructed. The system consists of six parallel tubes which can be filled with catalyst materials (particles, nets, monoliths). Different catalyst materials, particle sizes and temperatures were evaluated in catalytic three-phase hydrogenation of citral over Ni/SiO₂ catalyst. The reactor system showed good reproducibility.     

An efficient reformulation of the multiechelon stochastic inventory system with uncertain demands

It is shown that by reformulating the three‐stage multiechelon inventory system with specific exact linearizations, larger problems can be solved directly with mixed‐integer linear programming (MILP) without decomposition. The new formulation is significantly smaller in the number of continuous variables and constraints. An MILP underestimation of the problem can be solved as part of a sequential piecewise approximation scheme to solve the problem within a desired optimality gap.     

铣削刀具进展

随着制造商不断推出具有更强功能和更高效率的产品,零件的制造变得越来越复杂,难度也变得越来越高。除了具有复杂的轮廓和更严格的公差外,零件通常还采用高性能的材料制成,这虽然提供了所需的强度和可靠性,但也对可加工性产生了不利影响。刀具制造商持续不断地开发新型刀具,旨在最大限度地提升加工效率。铣刀技术的进步就是证明这种努力的一个典型例子。一直以来,整体硬质合金刀具都提供了极高的金属切除率和绝佳的精度。     

Efficient cross-validation for kernelized least-squares regression with sparse basis expansions

We propose an efficient algorithm for calculating hold-out and cross-validation (CV) type of estimates for sparse regularized least-squares predictors. Holding out H data points with our method requires O(min(H ² n,Hn ²)) time provided that a predictor with n basis vectors is already trained. In addition to holding out training examples, also some of the basis vectors used to train the sparse regularized least-squares predictor with the whole training set can be removed from the basis vector set used in the hold-out computation. In our experiments, we demonstrate the speed improvements provided by our algorithm in practice, and we empirically show the benefits of removing some of the basis vectors during the CV rounds.