Repliker : Replik på Anders Ramsays recension

Sociologisk Forsknings digitala arkiv

Mechanical and tribological properties of PVD-coated cemented carbide as evaluated by a new multi-pass scratch testing method

A new test method based on multipass scratch testing has been developed for evaluating the mechanical and tribological properties of thin, hard coatings. The proposed test method uses a pin-on-disc tribometer and during testing a Rockwell C diamond stylus is used as the “pin” and loaded against the rotating coated sample. The influence of normal load on the number of cycles to coating damage is investigated and the resulting coating damage mechanisms are evaluated by posttest scanning electron microscopy. The present study presents the test method by evaluating the performance of Ti0.86Si0.14N, Ti0.34Al0.66N, and (Al0.7Cr0.3)2O3 coatings deposited by cathodic arc evaporation on cemented carbide inserts. The results show that the test method is quick, simple, and reproducible and can preferably be used to obtain relevant data concerning the fatigue, wear, chipping, and spalling characteristics of different coating-substrate composites. The test method can be used as a virtually nondestructive test and, for example, be used to evaluate the fatigue and wear resistance as well as the cohesive and adhesive interfacial strength of coated cemented carbide inserts prior to cutting tests.

Microstructural, Mechanical and Tribological Characterisation of CVD and PVD Coatings for Metal Cutting Applications

The present thesis focuses on characterisation of microstructure and the resulting mechanical and tribological properties of CVD and PVD coatings used in metal cutting applications. These thin and hard coatings are designed to improve the tribological performance of cutting tools which in metal cutting operations may result in improved cutting performance, lower energy consumption, lower production costs and lower impact on the environment.  In order to increase the understanding of the tribological behaviour of the coating systems a number of friction and wear tests have been performed and evaluated by post-test microscopy and surface analysis. Much of the work has focused on coating cohesive and adhesive strength, surface fatigue resistance, abrasive wear resistance and friction and wear behaviour under sliding contact and metal cutting conditions. The results show that the CVD deposition of accurate crystallographic phases, e.g. α-Al2O3 rather than κ-Al2O3, textures and multilayer structures can increase the wear resistance of Al2O3. However, the characteristics of the interfaces, e.g. topography as well as interfacial porosity, have a strong impact on coating adhesion and consequently on the resulting properties.  Through the deposition of well designed bonding and template layer structures the above problems may be eliminated. Also, the presence of macro-particles in PVD coatings may have a significant impact on the interfacial adhesive strength, increasing the tendency to coating spalling and lowering the surface fatigue resistance, as well as increasing the friction in sliding contacts. Finally, the CVD-Al2O3 coating topography influences the contact conditions in sliding as well as in metal cutting. In summary, the work illuminates the importance of understanding the relationships between deposition process parameters, composition and microstructure, resulting properties and tribological performance of CVD and PVD coatings and how this knowledge can be used to develop the coating materials of tomorrow.

Sjuksköterskans upplevelse av humorns betydelse i psykiatrisk omvårdnad - En intervjustudie

Bakgrund: Sjuksköterskan förväntas arbeta med patientens bästa i fokus och hon möter många allvarliga situationer där själva existensen står på spel och där sjuksköterskan behöver härbärgera starka känslor hos patienter och deras närstående, men också upprätthålla sin egen integritet och känslomässiga balans. Humor har visats vara ett kraftfullt men tveeggat verktyg i kommunikation och relationsbyggande. Inom psykiatrin kan detta verktyg förmodas behöva hanteras med särskilt kunskap och omsorg. Syfte: Att beskriva hur sjuksköterskan i psykiatrisk omvårdnad ser på humor som företeelse och hennes upplevelse av positiva respektive negativa effekter av att använda humor. Metod: Undersökningen utfördes med en kvalitativ innehållsanalys av halvstrukturerade intervjuer med fem sjuksköterskor verksamma inom psykiatrisk omvårdnad. Resultat: Humor sågs som ett viktigt verktyg inom psykiatrisk omvårdnad som det krävdes lyhördhet, respekt, fingertoppskänsla och timing för att kunna använda. Den huvudsakliga strategin för att använda humor var öppenhet för spontant humor i mötet men det gavs även exempel på medvetna interventioner. Humor öppnade möjligheter att få se verkligheten från nya perspektiv vilket var verksamt för att förändra negativa tankar samt lätta på ångest och negativa känslor. Humor underlättade kommunikation och kunde användas för att jämna ut maktbalanser. Det fanns risk för negativa effekter om humor användes för att trycka ner andra eller som verklighetsflykt. Psykiatriska patienter uppfattades som mer sårbara och medvetenhet om hur svåra psykiska sjukdomar påverkar förmågan att uppfatta och uppskatta humor var viktig även om ett allmänt bra bemötande ansågs vara grundläggande. Slutsats: Positiva former av humor som används på ett respektfullt och inkännande sätt kan vara är ett viktigt verktyg i omvårdnaden för att möjliggöra nya perspektiv på tillvaron, ge lättnad i ångest, minska negativa känslor och tankar samt höja livskvaliteten för både patienter och personal i en verksamhet med mycket allvar.

Störningsinformation i tågtrafiken : Attityder bland resenärer och tågbolag till störningsinformation och tjänster för sådan information

When booking a trip along the railway through several train operators it is not uncommon that information about possible disruptions along the railway (that can change or cancel the booked trip) are not relayed to the passengers. Today, research on rail traffic in Sweden is limited. It is unclear how satisfied customers are with the quality of the information they receive during their trip (if they get it at all), including with respect to disruptions. Our partners have identified what they believe is a need among train operators, which is a service for disruption information to travelers. In addition to confirming that there is a need for such a service, we have an interest to investigate how such a service might look like and what the users want. Our research has shown that passengers are not satisfied with either the amount of information about disturbances or how often they get it. Along with KnowitBorlänge, we have come up with a proposed solution that uses already existing technologies to create a portal for an efficient way to get the interference information to travelers.

Investigation of material transfer in sliding friction-topography or surface chemistry?

To differentiate between the roles of surface topography and chemical composition on influencing friction and transfer in sliding contact, a series of tests were performed in situ in an SEM. The initial sliding during metal forming was investigated, using an aluminum tip representing the work material, put into sliding contact with a polished flat tool material. Both DLC-coated and uncoated tool steel was used. By varying the final polishing step of the tool material, different surface topographies were obtained. The study demonstrates the strong influence from nano topography of an unpolished DLC coated surface on both coefficient of friction and material transfer. The influence of tool surface chemistry is also discussed.

Sociala kartor över utbildningslandskapet : Installationsföreläsning, professuren i utbildningssociologi vid Uppsala universitet, 11 november 2015

Sociologisk Forsknings digitala arkiv