Mechanism of Insulin Emission in Matrix Assisted Laser Ionization

In the present paper the emission of intact insulin quasi-molecular ion [M+H] + during laser ablation (MALDI) is studied. It was observed in particular that the insulin TOF molecular peak increases as the laser power increases. The DE-Vestal method for the initial velocity measurements was improved theoretically including the distance (d0) until the free expansion regime can be considered. According to the present analysis, the v0 parameter given by the DE-Vestal method is interpreted as the initial velocity that the desorbed ion would have if no collision occurs in the plasma. The improved method interprets v 0 as the "final" initial velocity, i.e., as the velocity that the desorbed ions have when the plasma free expansion starts and, effectively, collisions no longer occur. The new method allows also the determination of d 0 , the distance to the solid when the free expansion starts. The data fitting shows that the distance (d0) has a linear dependence on the laser's intensity. Extrapolation of these values gives I = 0.69 G W cm −2 as the minimum energy density necessary to produce high density plasma during the insulin ions desorption when using αCHCA matrix

Measurement of isotopic separation of argon with the prototype of the cryogenic distillation plant Aria for dark matter searches

The Aria cryogenic distillation plant, located in Sardinia, Italy, is a key component of the DarkSide-20k experimental program for WIMP dark matter searches at the INFN Laboratori Nazionali del Gran Sasso, Italy. Aria is designed to purify the argon, extracted from underground wells in Colorado, USA, and used as the DarkSide-20k target material, to detector-grade quality. In this paper, we report the first measurement of argon isotopic separation by distillation with the 26 m tall Aria prototype. We discuss the measurement of the operating parameters of the column and the observation of the simultaneous separation of the three stable argon isotopes: 36Ar , 38Ar , and 40Ar . We also provide a detailed comparison of the experimental results with commercial process simulation software. This measurement of isotopic separation of argon is a significant achievement for the project, building on the success of the initial demonstration of isotopic separation of nitrogen using the same equipment in 2019

Evolution of acute lung injury/acute respiratory distress syndrome mortality in an ICU in Southern Brazil

Kada se ispituje trošenje alata postoji niz modela trošenja koji se uglavnom primjenjuju kod obrade metalnih materijala, ali ima mali broj onih za procjenu trošenja nehomogenih materijala, kao što je primjerice kamen . U teorijskom dijelu ovog rada biti će prikazani osnovni uzroci i mehanizmi trošenja alata, kao i oblici trošenja alata koji se mogu pojaviti zbog različitih uvjeta u kojima se nalazi alat tijekom obrade. Opisat će se Taylor-ov model trošenja i prikazati utjecaj različitih parametara obrade na trošenje alata. Kako će se u eksperimentalnom dijelu obrađivati kamen, u teorijskom dijelu će još biti obrađen utjecaj različitih materijala na trošenje alata, koji se koriste za obradu kamena. Detaljno će biti opisani postupci trošenja takvih alata, odnosno uvid u strukturu alata i procese koji se zbivaju tijekom obrade. Praćenje istrošenosti alata je veoma važno zbog pravovremene i brze reakcije s kojom se čuva alat, a time i kvaliteta proizvoda. U eksperimentalnom dijelu provodit će se bušenje kamena te će se pratiti utjecaj istrošenosti alata na vrijednosti posmične sile te vrijednosti struja glavnog i posmičnog motora. Nakon bušenja određenog broj provrta oštrice, svrdla će se slikati te će se procijeniti stupanj istrošenosti i usporediti iznos trošenja s izbušenom duljinom, kao i promjena sila i struje glavnog motora u odnosu na istrošenost alata.In examination of tool wear there is a lot of models that concern tool wear at cutting metallic materials but little number of those which concern evaluation of wear when cutting heterogeneous materials, for example a stone. In first part of this paper there will be shown basic causes and mechanism of tool wear, and also different types of tool wear that can appear due to different cutting conditions during cutting process. Taylor model of tool wear and influence of different process parameters on tool will be described. Because stone material will be used in experimental part of this paper, an influence of different materials on tool wear, which are commonly used in stone machining, will be shown. Detailed view of tool wear and processes which happen during machining will be presented. Tool wear monitoring is very important due to timely and quick response which helps to save the quality of the product. In the experiment section a drilling of stone material will be conducted and force and current of main spindle and feed motor will be monitored. After certain number of drilled holes tool cutting edges, using special camera, will be photographed and they will be used to evaluate a degree of tool wear and compare it to overall drilling length, with comparison to respective changes of force applied on tool and main spindle motor current

Heavy ion irradiation of condensed CO2: sputtering and molecule formation

International audienceContext : Ices present in different astrophysical environments are exposed to ion irradiation from cosmic rays (H to heavier than Fe) in the keV to GeV energy range. Aims : The objective of this work is to study the effects produced in astrophysical ices by heavy ions at relatively high energies (MeV) in the electronic energy loss regime and compare them with those produced by protons. Methods : C18O2 was condensed on a CsI substrate at 13 K and it was irradiated by 46 MeV 58Ni11+ up to a final fluence of 1.5 × 1013 cm−2 at a flux of 2 × 109 cm−2 s−1. The ice was analyzed in situ by infrared spectroscopy (FTIR) in the 5000−600 cm−1 range. Results : The CO2 destruction was observed, as well as the formation of other species such as CO, CO3, O3, and C3. The destruction cross section of CO2 is found to be 1.7×10−13 cm2, while those for the formation of CO, CO3, and O3 molecules are 1.6 × 10−13 cm2, 4.5 × 10−14 cm2, and 1.5 × 10−14 cm2, respectively. The sputtering yield of the CO2 ice is 4.0 × 104 molecules/impact, four orders of magnitude higher than for H projectiles at the same velocity. This allows us to estimate the contribution of the sputtering by heavy ions as compared to protons in the solar winds and in cosmic rays. Conclusions : The present results show that heavy ions play an important role in the sputtering of astrophysical ices. Furthermore, this work confirms the quadratic stopping power dependence of sputtering yields