Search results for "SSA"
showing 10 items of 6161 documents
Preconcentration and speciation analysis of mercury : 3D printed metal scavenger-based solid-phase extraction followed by analysis with inductively c…
2021
A selective method for preconcentration and determination of methylmercury (MeHg) and inorganic mercury (iHg) in natural water samples at the ng L−1 level has been developed. The method involves adsorption of Hg species into a 3D printed metal scavenger and sequential elution with acidic thiourea solutions before ICP-MS determination. Experimental parameters affecting the preconcentration of MeHg and iHg such as the sample matrix, effect of the flow rate on adsorption, eluent composition, and elution mode have been studied in detail. The obtained method detection limits, considering the preconcentration factors of 42 and 93, were found to be 0.05 ng L−1 and 0.08 ng L−1 for MeHg and iHg, res…
Hiilen taustavaikutukset muovien lisäaineille induktiivisesti kytketyssä plasmassa
2017
Tässä tutkielmassa tarkasteltiin hiilen matriisivaikutuksia induktiivisesti kytkettyä plasmaa (ICP) hyödyntävissä analyysimenetelmissä. Kirjallisessa osassa on tarkasteltu erilaisia kiinteiden näytteiden esikäsittelymenetelmiä kiinnittäen huomiota jäännöshiilimääriin. Lisäksi läpi käydään ICP-tekniikoiden teoriaa, laitteistoa ja häiriöitä, painotuksen ollessa hiilen aiheuttamissa ongelmatekijöissä. Kokeellisessa osassa tutkittiin onko hiilellä merkittäviä vaikutuksia muovien hivenaineille (As, Cd, Cr, Pb, Sb, Sn, Zn, S) sellaisissa pitoisuuksissa, joita jäännöshiilipitoisuudelta voidaan odottaa kiinteiden näytteiden esikäsittelyn jälkeen. Jäljitellen sertifioituja muovimateriaaleja valmiste…
Observation of an ultralow-Q-value electron-capture channel decaying to 75As via a high-precision mass measurement
2022
A precise determination of the atomic mass of 75As has been performed utilizing the double Penning trap mass spectrometer, JYFLTRAP. The mass excess is measured to be −73035.519(42)keV/c2, which is a factor of 21 more precise and 1.3(9)keV/c2 lower than the adopted value in the newest Atomic Mass Evaluation (AME2020). This value has been used to determine the ground-state–to–ground-state electron-capture decay Q value of 75Se and β− decay Q value of 75Ge, which are derived to be 866.041(81) keV and 1178.561(65) keV, respectively. Using the nuclear energy-level data of 860.00(40) keV, 865.40(50) keV (final states of electron capture), and 1172.00(60) keV (final state of β− decay) for the exc…
Mass of astrophysically relevant 31Cl and the breakdown of the isobaric multiplet mass equation
2015
The mass of $^{31}$Cl has been measured with the JYFLTRAP double Penning trap mass spectrometer at the Ion-Guide Isotope Separator On-Line (IGISOL) facility. The determined mass-excess value, -7034.7(34) keV, is 15 times more precise than in the Atomic Mass Evaluation 2012. The quadratic form of the isobaric multiplet mass equation for the T=3/2 quartet at A=31 fails ($\chi^2_n$=11.6) and a non-zero cubic term, d=-3.5(11) keV, is obtained when the new mass value is adopted. $^{31}$Cl has been found to be less proton-bound with a proton separation energy of $S_p$=265(4) keV. Energies for the excited states in $^{31}$Cl and the photodisintegration rate on $^{31}$Cl have been determined with s…
Self-Complementary Dimers of Oxalamide-Functionalized Resorcinarene Tetrabenzoxazines
2018
Self‐complementarity is a useful concept in supramolecular chemistry, molecular biology and polymeric systems. Two resorcinarene tetrabenzoxazines decorated with four oxalamide groups were synthesized and characterized. The oxalamide groups possessed self‐complementary hydrogen bonding sites between the carbonyls and amide groups. The self‐complementary nature of the oxalamide groups resulted in self‐included dimeric assemblies. The hydrogen bonding interactions within the tetrabenzoxazines gave rise to the formation of dimers, which were confirmed by single‐crystal X‐ray diffractions analysis and supported by NMR spectroscopy and mass spectrometry. The self‐included dimers were connected b…
Ion mobility-mass spectrometry of supramolecular complexes and assemblies
2019
Despite their structural and functional differences, synthetic supramolecular assemblies share many similarities with biological assemblies, especially enzymes. The assemblies can be on the same length scale, and their structures and guest binding are typically governed by non-covalent interactions. Thus, only relatively weak interactions define the shape of a synthetic supramolecule or the secondary and tertiary structure of a protein, such that the resulting dynamism makes structure elucidation challenging. For biomolecules such as peptides, proteins, glycans and lipids this has often been tackled using ion mobility–mass spectrometry (IM-MS), whereby analyte ions are separated according t…
Meccanica del volo dei velivoli ad ala fissa
2018
La meccanica del volo studia le traiettorie e le caratteristiche del moto di un aeromobile sotto l'azione delle forze aerodinamiche, propulsive e inerziali.
Simultaneous production of furfural and levulinic acid from pine sawdust via acid-catalysed mechanical depolymerization and microwave irradiation
2019
Abstract In this work pine sawdust was converted into levulinic acid (LA) and furfural. Sawdust was first pre-treated with sulfuric acid-catalysed mechanical depolymerization. The conversion reactions were then performed with microwave heating at 180 °C. To enhance the furfural yield and the efficient separation of furfural and LA, a biphasic water-toluene reaction system was used. The effect of an additional catalyst, AlCl3, on the yield of LA and furfural was also studied. According to the results the pre-treatment method enhanced the yields of LA. In addition, due to the microwave heating the reaction times were short. Additional AlCl3 catalyst enhanced the LA yield, however excellent fu…
"Media are your windows to the world" : teachers' perspectives on the use of media and ICT in foreign language teaching
2016
Eri medioita on käytetty opetuksessa jo vuosikymmeniä. Internetin ja sosiaalisen median käytön kasvun myötä uudentyyppiset mediat ovat ottaneet jalansijaa luokkahuoneissa ja niiden oppiainerajat ylittävään käyttöön kehotetaan myös uusimmissa opetussuunnitelmissa. Tämän tutkimuksen tarkoituksena on selvittää kuinka usein opettajat käyttävät eri medioita opetuksessaan ja vapaa-ajallaan, kuinka pedagogisesti hyödyllisiksi he kokevat eri mediatyypit ja kuinka hyvin he osaavat niitä itse käyttää opetuksessa. Tutkimuksen tarkoituksena on lisäksi saada tietoa siitä, mitkä ovat opettajien mielestä suurimmat hyödyt ja haasteet median opetuskäytössä ja siitä, minkälaista lisäkoulutusta medioiden käyt…
Archaeometric Characterisation of Decorated Pottery from the Archaeological Site of Villa dei Quintili (Rome, Italy): Preliminary Study
2019
This work focused on the study of decorated pottery dated back to the 16th century from the Roman archaeological site of Villa dei Quintili, a monumental complex located in the south-eastern part of Rome (Italy). A minero-petrographic and geochemical study was undertaken to analyse five archaeological samples in order to define textural features and raw materials used for their production, along with the chemical and physical composition of the superficial decorative glazed coatings. For this purpose, different analytical methods were used, such as polarising optical microscope (POM), X-ray diffraction (XRD), micro-Raman spectroscopy, X-Ray fluorescence (XRF), and electron microprobe analys…