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Unmanned aerial vehicles for the Joint Aeolus Tropical Atlantic Campaign
Franco Marenco, Griša Močnik, 2023, objavljeni povzetek znanstvenega prispevka na konferenci

Opis: During June 2022, the Cyprus Institute (CyI) took part in the ASKOS experiment in Mindelo, Cape Verde, with several of Unmanned Aerial Vehicles (UAVs), fitted with a number of in-situ aerosol instruments able to profile the Saharan Air Layer between the surface and an altitude of 5,300 m. In addition to ASKOS objectives, transnational access project Diurnal vAriation of the vertically resolved siZe distribution in the Saharan Air Layer  (DAZSAL) was also carried out at the same time. The campaign aimed at validating the Aeolus L2A product in the presence of dust and marine aerosols, estimating the influence on Aeolus products of non-spherical particles, evaluating the impact of particle orientation, and study the diurnal cycle of the dust size-distribution at high altitude. In this presentation we will present and discuss the scientific objectives, the context, the Unmanned Aerial Systems (UASs) that we developed in-house, and the instruments used, together with their limitations, calibration methods, uncertainties, challenges and difficulties encountered. We will also discuss the logistical and planning challenges that such a campaign entails.Operations took place from the Cesaria Evora International Airport. The instruments deployed on-board the UAVs permitted to evaluate the height-resolved particle size-distribution between 0.1 and 40 µm and detect cases of particle orientation, to complement the observations with ground-based remote sensing set out by NOA and TROPOS. Moreover, 24 high-altitude dust samples were collected on impactors, for further analysis by Scanning Electron Microscopy. In total, 25 scientific flights were performed on 12 flying days (almost half of which at night). Five flights were conducted during Aeolus overpasses. Weather has been a determining factor for both the ground-based remote sensing operations and the UAS operation, and airport traffic has been another constraint that needed to be accounted for, in the UAS operation.
Ključne besede: UAV, mineral dust, climate change, Aeolus satellite
Objavljeno v RUNG: 21.12.2023; Ogledov: 983; Prenosov: 3
.pdf Celotno besedilo (291,05 KB)
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Search for evidence of neutron fluxes using Pierre Auger Observatory data
Danelise De Oliveira Franco, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, objavljeni znanstveni prispevek na konferenci

Opis: Astrophysical neutral particles, such as neutrons, can point directly to their sources since they are not affected by magnetic fields. We expect neutron production in the immediate vicinity of the acceleration sites due to cosmic ray interactions. Hence, a high-energy neutron flux could help to identify sources of cosmic rays in the EeV range. Free neutrons, although unstable, can travel a mean distance of 9.2 kpc times their energy in EeV. Due to the neutron instability, we limit the searches to Galactic candidate sources. Since air showers initiated by a neutron are indistinguishable from those generated by a proton, we would recognize a neutron flux as an excess of events from the direction of its source. Previous searches using events with a zenith angle up to 60^◦ and energies above 1 EeV found no surplus of events that would indicate a neutron flux. We present the results of the search for evidence of high-energy neutron fluxes using a data set about three times larger than the previous work. We investigate the sky in the field of view of the Pierre Auger Observatory, narrowing down to specific directions of candidate sources. With respect to previous works, we extend the angular range up to zenith angles of 80^◦ , reaching declinations from −90^◦ to +45^◦ , and the energy range going as low as 0.1 EeV. The extension in the field of view provides exposure to the Crab Nebula for the first time.
Ključne besede: neutrons, cosmic ray, Pierre Auger Observatory, Crab Nebula, proton, high-energy neutron flux
Objavljeno v RUNG: 14.11.2023; Ogledov: 958; Prenosov: 5
.pdf Celotno besedilo (472,98 KB)
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TLS Detection in Liquid Chromatography, Flow Injection Analysis and Microfluidic Systems for Food Quality Control and Biomedical Diagnostics
Mladen Franko, 2023, predavanje na tuji univerzi

Opis: The basics of thermal lens spectrometry (TLS) and TLS microscopy (TLM) will be explained considering in particular the dependence of the thermal lens signal on the excitation power, thermo-optical properties of the sample, as well as sample flow and photostability of the analyte, with particular focus on the TLS enhancement factor, sensitivity and sample throughput of TLS and TLM measurements. Examples of applications will include most notable achievements of TLS and TLM measurements in liquid chromatography (detection of bilirubin and biliverdin in blood plasma, bilirubin in vascular endothelial cells), flow injection analysis (organophosphate insecticides and allergens in foodstuffs) and microfluidics (high throughput determination of Cr(VI), microcystin, HPV virus antibodies, and biomarkers of acute kidney injury). Before the concluding remarks, recent progress in multi-pass mode-mismatched TLS instrumentation and applications of incoherent light sources will be presented s part of the future outlook for TLS and TLM techniques.
Ključne besede: Spektrometrija TLS, TLM, chromatography, microfluidics, FIA
Objavljeno v RUNG: 14.11.2023; Ogledov: 943; Prenosov: 5
.pdf Celotno besedilo (21,62 MB)

Effects of Photodegradation in TLS Measurements: Troubleshooting and Applications in Photochemistry and Photocatalysis
Mladen Franko, 2023, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje)

Opis: Most analytical applications of thermal lens spectrometry (TLS) and related theoretical models consider absorbance of the sample constant during a single excitation by the pump laser beam. For photolabile analytes intensive excitation light can cause photodegradation, which significantly affects the results of TLS measurements. Theoretical models have been developed to account for changes in concentration and consequent changes in absorbance, caused by chemical reactions of different orders. Furthermore, abnormal TLS signal transients were observed for fast photochemical reactions on millisecond time scale, and the contributions of photodegradation as well as molecular diffusion were analyzed in detail. It has also been demonstrated that such effects can be reduced by performing TLS measurements in flowing systems such as in the case of flow injection analysis (FIA) or microfluidics. These findings were utilized to study the kinetics of chemical reactions, processes such as photostability of the soybean oil and thermal stability of biodiesel, or to improve the sensitivity of TLS detection in case of photolabile analytes. Furthermore, in combination with the concept of biomolecular recognition, FIA-TLS was exploited to study the efficiency of photocatalytic degradation of some neurotoxic substances such as organophosphate insecticides and revealed the formation of even more toxic degradation products. High sensitivity of TLS has enabled discrimination between photocatalytic and photosensitization mechanisms in photocatalytic degradation of textile dyes as well as between photodegradation and photocatalysis as will be demonstrated by the results of latest research in this field.
Ključne besede: Spektrometrija TLS, fotolabilnost, CrIVI), fotokataliza, fotorazgradnja
Objavljeno v RUNG: 23.10.2023; Ogledov: 1630; Prenosov: 0
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Recent Progress and Applications of Thermal Lens Spectrometry and Photothermal Beam Deflection Techniques in Chemical Analysis and Materials' Characterization
Mladen Franko, 2023, predavanje na tuji univerzi

Opis: Initially the theoretical background relevant to recent developments of thermal lens spectrometry (TLS) which include TLS detection in liquid chromatography and in microfluidic flow injection analysis (μFIA) and to non-contact and non-destructive characterization of composite materials by beam deflection spectrometry (BDS) is presented. The advantages and basic characteristics of the TLS and BDS techniques are illustrated by presenting applications such as the determination of free bilirubin in endothelial cells by HPLC-TLS, studies of diffusion in Taylor-type microfluidic flows by thermal lens microscopy (TLM), μFIA-TLM detection of microcystin-LR and Cr(VI) in waters, and by the dept profiling of multi-layered coatings of orthopaedic implants. In the main part of the presentation the results of joint MU-UNG research are presented with emphasis on BDS and TLS characterisation of biocomposite materials from cellulose and chitosan or keratin with added Ag nanoparticles, sporopollenin capsules or antibiotics. The focus is on BDS determination of thermal parameters including thermal diffusivity and related properties relevant for medical applications, such as porosity and surface roughness, as well as on the TLS detection of Ag and other nanoparticles applied in studies of nanoparticle leaching from biocomposites.
Ključne besede: Optotermična spektrometrija, TLS, BDS, kemijska analiza, karakterizacija materialov, biokompoziti
Objavljeno v RUNG: 23.10.2023; Ogledov: 908; Prenosov: 2
.pdf Celotno besedilo (25,02 MB)

Recent progress and applications of thermal lens spectrometry in environmental and bio-medical sensing
Mladen Franko, 2023, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje)

Opis: Applications of TLS in environmental and bio-medical sensing, which include determination of iron species and ammonia by TLS and comparison to their microfluidic TLM detection are presented. Advantages of microfluidic FIA-TLM in terms of sensitivity and high sample throughput for determination of microcystin, Cr(VI) and HPV virus are discussed.
Ključne besede: Optotermična spektrometrija TLS, biomedicinska diagnostika, monitoring okolja
Objavljeno v RUNG: 19.10.2023; Ogledov: 1086; Prenosov: 4
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Frontiers in chemistry

Ključne besede: kemija, kemijske spojine, elektronske revije
Objavljeno v RUNG: 19.10.2023; Ogledov: 960; Prenosov: 2
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