Search results for "happamuus"
showing 4 items of 4 documents
Microscopic Insights Into the Formation of Methanesulfonic Acid–Methylamine–Ammonia Particles Under Acid-Rich Conditions
2022
Understanding the microscopic mechanisms of new particle formation under acid-rich conditions is of significance in atmospheric science. Using quantum chemistry calculations, we investigated the microscopic formation mechanism of methanesulfonic acid (MSA)–methylamine (MA)–ammonia (NH3) clusters. We focused on the binary (MSA)2n-(MA)n and ternary (MSA)3n-(MA)n-(NH3)n, (n = 1–4) systems which contain more acid than base molecules. We found that the lowest-energy isomers in each system possess considerable thermodynamic and dynamic stabilities. In studied cluster structures, all bases are protonated, and they form stable ion pairs with MSA, which contribute to the charge transfer and the stab…
Laser-induced tuning of graphene field-effect transistors for pH sensing
2023
Here we demonstrate, using pulsed femtosecond laser-induced two-photon oxidation (2PO), a novel method of locally tuning the sensitivity of solution gated graphene field-effect transistors (GFETs) without sacrificing the integrity of the carbon network of chemical vapor deposition (CVD) grown graphene. The achieved sensitivity with 2PO was (25 ± 2) mV pH−1 in BIS-TRIS propane HCl (BTPH) buffer solution, when the oxidation level corresponded to the Raman peak intensity ratio I(D)/I(G) of 3.58. Sensitivity of non-oxidized, residual PMMA contaminated GFETs was 20–22 mV pH−1. The sensitivity decreased initially by 2PO to (19 ± 2) mV pH−1 (I(D)/I(G) = 0.64), presumably due to PMMA residue remova…
Dietary acid load and acid-base balance in exercise and health from adolescence to late adulthood
2018
This thesis investigated whether dietary acid load has either short-term (4 to 7 days) or prolonged (12 weeks) effects on acid-base status at rest and during submaximal and maximal aerobic exercise; whether the effects of dietary acid load on acid-base status differ between adolescents, young adults and the elderly, and between men and women; and whether the changes in acid-base balance have a further effect on aerobic exercise performance. These questions were addressed in three different study settings in healthy and recreationally active men and women. In studies 1 and 2, which followed a crossover study design, participants were assigned in randomized order to follow a diet with a low o…
Lignoselluloosan happamassa esikäsittelyssä poistuvat hiilihydraatit
2017
Tämän lisensiaattitutkielman kirjallisessa osassa esitettiin kuvaus biomassoista, (ligno- selluloosamateriaalit) ja niihin pohjautuvien jalostettujen polttoaineiden tuotannon haasteista ja kustannuksta sekä tarkasteltiin biomassaraaka-aineiden esikäsittelymene- telmiä. Tarkastelun pohjana oli Suomen kasvuoloissa yleisimpien lingoselluloosa- materiaalien, havu- ja lehtipuun sekä ruokohelpin, soveltuminen bioetanolituotantoon niin integroituna perinteisen sellutehtaan yhteyteen kuin myös omana erillisenä tuo- tantonaan. Tutkielman kokeellisessa osassa analysoitiin eri esikäsittelymenetelmien, laimean ja väkevän rikkihappokäsittelyn sekä vesikäsittelyn vaikutusta tuotetun hydrolysaatin koostum…