Solid State Lasers for Stereolithography

Stereolithography is a Rapid Prototyping & Manufacturing (RP&M) technique which is used to produce 3 dimensional plastic parts directly out computer files generated by CAD. Stereolithography systems use ultraviolet lasers to solidify liquid resin into the desired form as defined by the CAD file. In recent years, solid state laser technology has reached the point where it can be applied to stereolithography (SL). Frequency tripling of the powerful lines of diode pumped NdlYAG, Nd/YV04, and Nd/YLF lasers results in wavelengths of 355 nm (YAG, YV04), 351 nm (YLF), and 349 nm (YLF). All these lines are applicable for SL. Commercial diode pumped lasers with tens or even hundreds milliwatts in the ultraviolet are already available. Efficient frequency tripling of the Nd/YAG, Nd/YV04 , or Nd/YLF lasers requires pulsed operation. The pulse repetition rates at maximum average power are typically between 1 and 30 kHz. This talk describes the issues relating to the applications of pulsed all solid state lasers in SL.Mechanical Engineerin

Fabrication of Parts Containing Small Features using Stereolithography

The StereoLithography (SL) process has benefited from many advances in the last four to five years. These include new resins with reduced shrinkage and curl distortion, enhanced software, and improved scanning techniques. One can produce highly accurate parts for most dimensions within a few mils of the design value as shown in numerous accuracy and benchmarking studies. SLA systems use a laser beam focused to a spot size of 200 -250 ~m. This limits the range of applications where SL can provide accurate models to parts which do not contain very small features i. e. wall thickness values less than about 300 ~m. Industries that manufacture products involving components with small features include electronics and medical. In this presentation we describe an extension of the SL technology to applications involving small features. This capability is achieved by reducing the laser focal spot size in an SLA-250 to 75 ~m. The technological principle behind the spot size reduction is described in the presentation, together with process issues and applications ofthe technology.Mechanical Engineerin

Poor neural and perceptual phoneme discrimination during acoustic variation in dyslexia

Whereas natural acoustic variation in speech does not compromise phoneme discrimination in healthy adults, it was hypothesized to be a challenge for developmental dyslexics. We investigated dyslexics’ neural and perceptual discrimination of native language phonemes during acoustic variation. Dyslexics and non-dyslexics heard /æ/ and /i/ phonemes in a context with fo variation and then in a context without it. Mismatch negativity (MMN) and P3a responses to phoneme changes were recorded with electroencephalogram to compare groups during ignore and attentive listening. perceptual phoneme discrimination in the variable context was evaluated with hit-ratios and reaction times. MMN/N2bs were diminished in dyslexics in the variable context. Hit-ratios were smaller in dyslexics than controls. MMNs did not differ between groups in the context without variation. These results suggest that even distinctive vowels are challenging to discriminate for dyslexics when the context resembles natural variability of speech. This most likely reflects poor categorical perception of phonemes in dyslexics. Difficulties to detect linguistically relevant invariant information during acoustic variation in speech may contribute to dyslexics’ deficits in forming native language phoneme representations during infancy. Future studies should acknowledge that simple experimental paradigms with repetitive stimuli can be insensitive to dyslexics’ speech processing deficits.Peer reviewe

Musicianship facilitates the processing of Western music chords-An ERP and behavioral study

Peer reviewe

EKP:n rahapolitiikan strategia ja euroalueen taloudellinen kehitys strategian näkökulmasta

Tiivistelmä. Tässä kandidaatintutkielmasssa perehdytään Euroopan keskuspankin rahapolitiikan strategiaan, ja analysoidaan euroalueen talouskehitystä strategian näkökulmasta. Osassa 1 eritellään strategian, rahapolitiikan strategian ja rahapolitiikan strategian historiallista kehitystä EKP:n osalta. Strategian historia esitellään kronologisesti vuodesta 1999, vuoden 2021 loppuun, jolloin strategiaa on viimeksi tarkistettu. Seuraavan tarkistuksen oletetaan tapahtuvan näillä näkymin vuonna 2025. Osassa 2 esitellään rahapoliittisiin muuttujiin ja indikaattoreihin liittyvää grafiikkaa, kuten raha-aggregaatit, inflaatio sekä ’korkokäytävä’. Graafinen tarkastelu keskittyy rahapolitiikan virityksen ja makromuuttujien tarkasteluun. Graafisen analyysin ja sen sanallisen tulkinnan on tarkoitus vastata alustavasti kysymykseen, onko EKP onnistunut rahapolitiikkansa strategian jalkauttamisessa, ja onko se toteuttanut strategiaansa käytännössä