Analysis of the influence of cutting parameters on surface roughness in laser cutting of tungsten alloy using control charts

Rad predstavlja analizu utjecaja parametara rezanja na hrapavost površine tijekom CO2 rezanja laserom legure volframa uporabom nitrogena kao pomoćnog plina, zasnovanu na kontrolnim kartama izrađenim pristupom statističke kontrole procesa. Zavisna varijabla je hrapavost površine, dok su neovisne varijable snaga lasera i brzina rezanja. Kontrolna karta koja se koristi u ovom radu je karta promjenjivih srednjih vrijednosti, koja potrebne srednje vrijednosti i raspone uzoraka proračunava uporabom tri uzastopne pojedinačne mjerne vrijednosti. Uporabom kriterija koji se često koriste u metodama statističke kontrole podataka za provjeru da li je situacija "izvan kontrole" može se zaključiti da povećanje brzine rezanja vodi k pogoršanju kontrole procesa s manjom uporabljenom snagom lasera.The paper presents analysis of the influence of cutting parameters on surface roughness during CO2 laser cutting process of tungsten alloy by using nitrogen as assist gas, based on control charts made by statistical process control (SPC) approach. Dependent variable is surface roughness, while independent variables are laser power and cutting speed. The control chart used within this paper is a variation of the moving means chart of experimental data samples, that calculates mean and range values using the three consecutive individual values. Applying the criteria often used in the SPC methods for the assessment of "out of control" situations, it may be inferred that increasing the cutting speed leads to worsening of control status for the process with lower laser power used

MeDir-OP, a Mediterranean directory for operational oceanography developed within the MAMA Project

The Mediterranean network to Assess and upgrade the Monitoring and forecasting Activity (MAMA), a 3-year thematic network project shared by leading marine research institutions from all the Mediterranean countries, has contributed to strengthening the institutional and scientific platform for the establishment of operational oceanography in the region. A key task in the MAMA project consisted in the stocktaking of activities and identifi- cation of current capabilities in operational oceanography on a country basis with a focus on availability of technological infrastructures, human resources and funding, applica- tions and product needs. The information was collected by: 1. Country Profiles on the operations of institutes/agencies/organisations dealing with marine monitoring; national structures supporting such activities and marine affairs in general; relevance of marine sectors in the economic activities of each country 2. a structured questionnaire targeting a comprehensive inventory on the routine marine monitoring activities in the Mediterranean. The Mediterranean Directory on Operational Oceanography (MeDir-OP) presents this information through the use of a user-friendly internet-based graphical interface allowing easy viewing of the metadata according to a number of categories. Specific information sets are collated into searchable mini-databases. MeDir-OP provides the basis for assessing the needs and potentials for operational oceanography in the region. It serves as an essential step to identifying gaps in infrastruc- tures, to underpin further research and technological developments specific to the region, and to designing an observing system that meets the needs of end-users.peer-reviewe