Investigation of wetting behaviour of hardenable copper based-alloys for brazing applications

ABSTRACT

Tools for machining are exposed to high loads, wear, and elevated temperatures. Commonly, such tools consist of cemented carbides and tool steel. To combine the advantages of both materials, high-quality-joints with high strengths are desired. When brazing these materials, the main challenge is the mismatch of the Coefficient of Thermal Expansion (CTE) and the poor wettability of cemented carbides by molten filler alloys. In this regard, the feasibility of two custom-made alloys (CuNi12Si5, CuNi12Si5B0.4) was analysed. Besides being a cost-efficient alternative, these alloys offer the possibility to modify their mechanical properties by precipitation hardening to reduce stresses within the final joints. Thus, this paper shows that a temperature of 1060°C is suitable for wetting and brazing tests on different substrates.     

Ignitability of decomposed transformer fluids

The effects of an electrical field (12 KV/cm) and elevated temperature (300°C) on the ignition potential of transformer fluids, which are candidate replacements for polychlorinated biphenyls (PCBs), have been studied. The combined results indicate that the chemical composition of the fluids were alerted, often in such a manner as to increase the ease of ignition. Exploratory Fire Research Center for Fire Research national Bureau of Standards     

Organic groups and molecular weight distribution in tertiary effluents and renovated waters

Group composition and MW distribution of soluble organics in effluents from successive biological and chemical treatment stages were investigated.In secondary effluents, most of the organics fell within the high MW range. Lime treatment caused marked reduction of the latter group, combined with removal of proteins, humics, and carbohydrates. (The overall removal amounted to approx. 65–75%). Simultaneously, there was an increase in the lowest MW range group—strongly hydrophilic, unidentifiable compounds outside the classification scheme used.     

Cardiac- versus diaphragm-based respiratory navigation for proton spectroscopy of the heart

Magnetic Resonance Materials in Physics, Biology and Medicine - To study inter-individual differences of the relation between diaphragm and heart motion, the objective of the present study was to...     

Sorption of organics on clay and synthetic humic-clay complexes simulating aquifer processes

Sorption/partition of several organic solute (contaminants) of a wide range of hydrophobicities was studied on clay and on clay-humic complexes representing aquifer-soil systems. The role of the mineral and of the organic (humic) fractions was elucidated and a model considering both fractions in the sorption process was proposed. The adsorption constants on humic (organic fraction), K_∝, were 8–20 times higher than on “pure” clay, K_m. But with soils with low to medium organic fractions (ƒ_∝ < 0.05) the contribution of the clay mineral to adsorption was quite significant, in spite of the fact that half of the sorption sites on the mineral surface were blocked by the humic. In the range of very low organic content in aquifer soil a non-linear pattern going through a minimum is observed between the overall partition coefficient and soil-organic fraction, transforming to the familiar linear relationship at higher ƒ_∝s. Both the K_∝ and K_m followed the linear-free energy relationship to the octanol-water partition coefficient K_ow.     

Identification of explosives with two-dimensional ultraviolet resonance Raman spectroscopy

The first two-dimensional (2D) resonance Raman spectra of TNT, RDX, HMX, and PETN are measured with an instrument that sequentially and rapidly switches between laser wavelengths, illuminating these explosives with forty wavelengths between 210 nm and 280 nm. Two-dimensional spectra reflect variations in resonance Raman scatter with illumination wavelength, adding information not available from single or few one-dimensional spectra, thereby increasing the number of variables available for use in identification, which is especially useful in environments with contaminants and interferents. We have recently shown that 2D resonance Raman spectra can identify bacteria. Thus, a single device that identifies the presence of explosives, bacteria, and other chemicals in complex backgrounds may be feasible.     

A technique for contactless measurement of water temperature using Stokes and anti-Stokes comparative Raman spectroscopy

Contactless measurements of water temperature are utilized in a number of sciences, such as oceanography, climatology, and biology. Previously reported Raman spectroscopy techniques exploited the changes in the shapes of water Raman bands. Interpretation of these changes is difficult since these bands are composed of multiple lines, each influenced not only by temperature but also by pressure and salinity. This paper presents a proof-of-principal demonstration of a contactless technique which determines water temperature from the ratio of Stokes and anti-Stokes intensities of the water 180 cm(-1) Raman band. This ratio is not sensitive to pressure and salinity, allowing reliable determination of water temperature.     

From first-order logic to automated word generation for Lyee

A conceptual schema can be viewed as a language to describe the phenomena in a system to be modelled, i.e. a set of derivation rules and integrity constraints as well as a set of event-rules describing the behaviour of an object system. In this paper, we investigate the relationship between the Lyee software requirements concepts with various constructs in conceptual modelling. Within our work we choose the Unified Modelling Language (UML) as a modelling notation for explaining conceptual models. The result obtained models a fully expressive set of UML and First Order Logic constructs mapped into Lyee concepts.