Defect Detection in Copper Products with an Infrared Line Scanner

Copper products are used in a variety of industrial applications like heat sinks, electrical components, etc. The specific parts are originally manufactured from copper raw material, which the process will form into long tubes or wires having various kinds of different cross sections. The process usually generates several hundreds of meters of this wire, which is wound on a big drum. The drum is eventually sold to the manufacturer of the electric components, for example. However, defects can also occur in the manufacturing process. The defects usually take the form of delaminations, and because of the fast drawing speeds of the tube or wire, the delaminations can be several meters long. Another type of defect that forms in the product is a small air bubble. If heat is applied to the product, the bubble may burst open leaving a hole in the surface

Photothermal Inspection of Impact Damages on Carbon-Glass Fibre Composites Using a Simple Hand Scanner Measurement System

Composite plates having durable and lightweight structure are most interesting materials considering several applications. Because durability is a major criteria, it is important to develop methods for finding flaws that affect this quality. In the case of carbon-glass fibre composites we have earlier demonstrated the suitability of radio frequency (RF) induction heating combined with IR-detection [1]. Based on the good experiences obtained with the method, a suitable equipment for field experiments was developed. Last year we showed the feasibility of a transportable thermal NDT equipment using laser line heating [2]. Modifying this measurement system for RF induction heating, several disadvantages of laser heating can be overcome

Stirring the Construction Project Management with Co-creation and Continuous Improvement

AbstractGathering information that is capable to explain customers’ needs is usually seen as a quite straightforward part of the traditional construction process: a customer should be able to tell all relevant needs in the first stage so that a building could be designed and built according to the gained information. But the process is lacking of service abilities if a customer wants to modify the given information due to a change in circumstances, albeit such a change is easily caused due turbulent economic situations and long spans in real-estate development projects. Hence the customer perspective regarding the construction management (CM) process should be accommodated better. In this paper, the case studies of the four premises improvement projects are reported upon, where the CM process was altered to include and apply the concepts of continuous improvement and co-creation. The process documentation covered the impacts of the case project on the usability of the premises, the indoor climate conditions (carbon dioxide and temperature) metering, the time lapse cameras and the on-line user feedback system. The documentation consists of the minutes of the meetings, the financial reporting and the time tables.Both the processes and the results of the projects are analysed. Based on the key findings, some suggestions are put forth upon how to improve the CM process to better serve customer interests and quality improvement in the future

Integrity of APS, HVOF and HVAF sprayed NiCr and NiCrBSi coatings based on the tensile stress-strain response

The interlamellar cohesion of thermal spray coatings influences greatly their mechanical properties and ability to use coatings in different loading conditions and wear/erosion resistance. In the present study, micro-tensile testing of free-standing coatings was utilized to evaluate the mechanical response of thermally sprayed coatings. In addition, the longitudinal uniaxial fracture strength of free-standing coatings could be determined by a tensile test. The coating materials studied were NiCr and NiCrBSi coatings sprayed by atmospheric plasma spraying (APS), high velocity oxy-fuel (HVOF), and high velocity air-fuel (HVAF) processes. The different materials used for the coatings sprayed by different methods yield different microstructures, different stress-strain relation in tensile testing. Different tensile test response was found to be related to cohesion strength between lamellas, and thus was affecting the cavitation erosion wear. The effect of other factors such as hardness and residual stresses on cavitation resistance were also discussed. Such results are crucial to understand the suitability of microstructures obtained by TS processes for different wear conditions.publishedVersionPeer reviewe

On the Applicability of Iron-Based Coatings Against Abrasion and Cavitation Erosion Wear

Iron-based coatings are often considered as replacement of hard chromium and WC-Co, as they pose lower health and environmental impact. In many cases, the combination of mechanical and chemical properties of iron-based alloys may be satisfactory and their relatively low cost makes these coatings an interesting candidate for many applications. This study is inspired by opportunities to harden the iron-base materials by strain hardening, solid solution strengthening, and precipitation hardening. Already commercially available Fe-based coating materials with precipitates of mixed carbides and borides in the metastable austenitic matrix achieve a high hardness. In this study, the cavitation erosion and abrasion resistance of various Fe-based coatings produced by HVAF and HVOF processes were investigated. Four experimental precipitates containing materials were prepared, and the sprayed coatings were tested for abrasive wear and cavitation erosion. In addition to precipitates, the contributions of martensite and retained austenite phases were investigated by influencing the microstructure through heat treatments, as the ability of these phases to influence ductility and toughness can be crucial to achieve the desired material properties. The properties of experimental and two commercial Fe-based alloys are compared with WC-Co and Cr3C2-NiCr coatings by property mapping.publishedVersionPeer reviewe

Recycling of Superbase-Based Ionic Liquid Solvents for the Production of Textile-Grade Regenerated Cellulose Fibers in the Lyocell Process

This article has a correction concerning the authors: We regret that there is an error with the author list in our original article. The authors Jussi Helminen, Paulus Hyväri, and Ilkka Kilpeläinen, all with the Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland, were mistakenly omitted. The author list should be as shown above in this Addition and Correction. DOI 10.1021/acssuschemeng.0c07773Ioncell is a Lyocell based technology for the production of manmade cellulose fibers. This technology exploits the intrinsic dissolution power of superbase-based ionic liquids (ILs) toward cellulose and the ability to form spinnable cellulose solutions. The regenerated fibers are produced via a dry-jet wet spinning process in which the cellulose filaments are stretched in an air gap before regenerating in an aqueous coagulation medium. For the commercialization of this process, it is essential to demonstrate the quantitative recovery of the solvent from the coagulation bath without impairing its solvation power. This study reports on the spinnability and recyclability of the IL 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-enium acetate ([mTBDH][OAc]) over five cycles in comparison to 1,5-diaza-bicyclo[4.3.0]non-5-enium acetate ([DBNH][OAc]). The aqueous IL solutions were recovered from the coagulation bath by successive thermal treatments under reduced pressure. Accordingly, the recycled ILs were utilized to dissolve 13 wt % cellulose pulp in each cycle without the addition of make-up IL. While using [mTBDH][OAc], the pulp was completely dissolved and processed into easily spinnable cellulose solutions during all five cycles, whereas the ability to dissolve pulp was completely lost after the first recovery cycle when using [DBNH][OAc]. The composition of the recovered ILs and extent of side-products generated in the adopted process was analyzed in detail. This includes characterization of the rheological properties of the solutions as well as the macromolecular and mechanical properties of the regenerated fibers. In addition, we review the toxicity of both solvents using Vibrio fischeri bacteria. Finally, the spun fibers from all [mTBDH][OAc] spinning trials were combined to produce a demonstration dress (Paju), designed and sewn by Marimekko Design House in Finland.Peer reviewe

Planck intermediate results. XV. A study of anomalous microwave emission in Galactic clouds

Anomalous microwave emission (AME) is believed to be due to electric dipole radiation from small spinning dust grains. The aim of this paper is a statistical study of the basic properties of AME regions and the environment in which they emit. We used WMAP and Planck maps, combined with ancillary radio and IR data, to construct a sample of 98 candidate AME sources, assembling SEDs for each source using aperture photometry on 1°-smoothed maps from 0.408 GHz up to 3000 GHz. Each spectrum is fitted with a simple model of free-free, synchrotron (where necessary), cosmic microwave background (CMB), thermal dust, and spinning dust components. We find that 42 of the 98 sources have significant (>5σ) excess emission at frequencies between 20 and 60 GHz. An analysis of the potential contribution of optically thick free-free emission from ultra-compact H ii regions, using IR colour criteria, reduces the significant AME sample to 27 regions. The spectrum of the AME is consistent with model spectra of spinning dust. Peak frequencies are in the range 20−35 GHz except for the California nebula (NGC 1499), which appears to have a high spinning dust peak frequency of (50 ± 17) GHz. The AME regions tend to be more spatially extended than regions with little or no AME. The AME intensity is strongly correlated with the sub-millimetre/IR flux densities and comparable to previous AME detections in the literature. AME emissivity, defined as the ratio of AME to dust optical depth, varies by an order of magnitude for the AME regions. The AME regions tend to be associated with cooler dust in the range 14−20 K and an average emissivity index, βd, of +1.8, while the non-AME regions are typically warmer, at 20−27 K. In agreement with previous studies, the AME emissivity appears to decrease with increasing column density. This supports the idea of AME originating from small grains that are known to be depleted in dense regions, probably due to coagulation onto larger grains. We also find a correlation between the AME emissivity (and to a lesser degree the spinning dust peak frequency) and the intensity of the interstellar radiation field, G0. Modelling of this trend suggests that both radiative and collisional excitation are important for the spinning dust emission. The most significant AME regions tend to have relatively less ionized gas (free-free emission), although this could be a selection effect. The infrared excess, a measure of the heating of dust associated with H ii regions, is typically >4 for AME sources, indicating that the dust is not primarily heated by hot OB stars. The AME regions are associated with known dark nebulae and have higher 12 μm/25 μm ratios. The emerging picture is that the bulk of the AME is coming from the polycyclic aromatic hydrocarbons and small dust grains from the colder neutral interstellar medium phase. Reproduced with permission from Astronomy & Astrophysics, © ESO 201

Defect Detection in Copper Products with an Infrared Line Scanner

Copper products are used in a variety of industrial applications like heat sinks, electrical components, etc. The specific parts are originally manufactured from copper raw material, which the process will form into long tubes or wires having various kinds of different cross sections. The process usually generates several hundreds of meters of this wire, which is wound on a big drum. The drum is eventually sold to the manufacturer of the electric components, for example. However, defects can also occur in the manufacturing process. The defects usually take the form of delaminations, and because of the fast drawing speeds of the tube or wire, the delaminations can be several meters long. Another type of defect that forms in the product is a small air bubble. If heat is applied to the product, the bubble may burst open leaving a hole in the surface.</p

Detection of Vertical Cracks in Carbon Fiber Composites Using an Infrared Line Scanner

Vertical cracks are among the most problematic types of defects from the thermal nondestructive testing (NDT) point of view. Nowadays, the fast thermal inspection techniques most commonly utilize infrared cameras and pulsed heating provided by flash lamps. The flash lamps illuminate the whole surface of a sample, and the resulting heat flow is mostly perpendicular to the surface. Therefore, the heat signature caused by the vertical cracks may be very small, and the cracks may avoid detection.</p